<?xml version="1.0" encoding="US-ASCII" standalone="no"?>
    <!-- Field: Doc-Info; Name: Generator; Value: GoXBRL; Version: 4.24a -->
    <!-- Field: Doc-Info; Name: VendorURI; Value: http://www.novaworks.co -->
    <!-- Field: Doc-Info; Name: Source; Value: CASS 0918 10Q.xfr; Date: 2018%2D11%2D02T13:44:51Z -->
    <!-- Field: Doc-Info; Name: Status; Value: 0x00000000 -->
<link:linkbase xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xbrli="http://www.xbrl.org/2003/instance" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
    <link:roleRef roleURI="http://cassinfo.com/role/cass-daei" xlink:href="cass-20180930.xsd#cass-daei" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-cbs" xlink:href="cass-20180930.xsd#cass-cbs" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-cbsp" xlink:href="cass-20180930.xsd#cass-cbsp" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-csoi" xlink:href="cass-20180930.xsd#cass-csoi" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/ConsolidatedStatementsOfComprehensiveIncome" xlink:href="cass-20180930.xsd#ConsolidatedStatementsOfComprehensiveIncome" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/ConsolidatedStatementsOfCashFlows" xlink:href="cass-20180930.xsd#ConsolidatedStatementsOfCashFlows" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-bop" xlink:href="cass-20180930.xsd#cass-bop" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-ia" xlink:href="cass-20180930.xsd#cass-ia" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-eps" xlink:href="cass-20180930.xsd#cass-eps" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-sr" xlink:href="cass-20180930.xsd#cass-sr" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-isi" xlink:href="cass-20180930.xsd#cass-isi" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-lbt" xlink:href="cass-20180930.xsd#cass-lbt" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-cac" xlink:href="cass-20180930.xsd#cass-cac" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-sc" xlink:href="cass-20180930.xsd#cass-sc" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-dpp" xlink:href="cass-20180930.xsd#cass-dpp" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-it" xlink:href="cass-20180930.xsd#cass-it" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-iis" xlink:href="cass-20180930.xsd#cass-iis" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-fvofi" xlink:href="cass-20180930.xsd#cass-fvofi" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-se" xlink:href="cass-20180930.xsd#cass-se" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-iat" xlink:href="cass-20180930.xsd#cass-iat" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-epst" xlink:href="cass-20180930.xsd#cass-epst" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-isit" xlink:href="cass-20180930.xsd#cass-isit" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-lbtt" xlink:href="cass-20180930.xsd#cass-lbtt" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-cact" xlink:href="cass-20180930.xsd#cass-cact" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-sct" xlink:href="cass-20180930.xsd#cass-sct" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-dppt" xlink:href="cass-20180930.xsd#cass-dppt" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-iist" xlink:href="cass-20180930.xsd#cass-iist" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-fvofit" xlink:href="cass-20180930.xsd#cass-fvofit" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-iand" xlink:href="cass-20180930.xsd#cass-iand" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-iasociad" xlink:href="cass-20180930.xsd#cass-iasociad" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-epsd" xlink:href="cass-20180930.xsd#cass-epsd" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-srd" xlink:href="cass-20180930.xsd#cass-srd" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-isid" xlink:href="cass-20180930.xsd#cass-isid" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-lbtsolcd" xlink:href="cass-20180930.xsd#cass-lbtsolcd" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-lbtsoaolblcd" xlink:href="cass-20180930.xsd#cass-lbtsoaolblcd" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-lbtsoceolpd" xlink:href="cass-20180930.xsd#cass-lbtsoceolpd" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-lbtsoaflld" xlink:href="cass-20180930.xsd#cass-lbtsoaflld" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-cacnd" xlink:href="cass-20180930.xsd#cass-cacnd" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-cacsocccod" xlink:href="cass-20180930.xsd#cass-cacsocccod" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-scnd" xlink:href="cass-20180930.xsd#cass-scnd" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-scsorsad" xlink:href="cass-20180930.xsd#cass-scsorsad" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-scsocsad" xlink:href="cass-20180930.xsd#cass-scsocsad" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-dppnd" xlink:href="cass-20180930.xsd#cass-dppnd" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-dppsonppcd" xlink:href="cass-20180930.xsd#cass-dppsonppcd" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/IncomeTaxesDetails" xlink:href="cass-20180930.xsd#IncomeTaxesDetails" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/InvestmentInSecuritiesNarrativeDetails" xlink:href="cass-20180930.xsd#InvestmentInSecuritiesNarrativeDetails" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-iissoisd" xlink:href="cass-20180930.xsd#cass-iissoisd" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-iissofvoswuld" xlink:href="cass-20180930.xsd#cass-iissofvoswuld" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-iissoacafvoisd" xlink:href="cass-20180930.xsd#cass-iissoacafvoisd" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/cass-fvofid" xlink:href="cass-20180930.xsd#cass-fvofid" xlink:type="simple" />
    <link:roleRef roleURI="http://cassinfo.com/role/SubsequentEventsDetails" xlink:href="cass-20180930.xsd#SubsequentEventsDetails" xlink:type="simple" />
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-daei" xlink:title="00000001 - Document - Document and Entity Information" />
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-cbs" xlink:title="00000002 - Statement - CONSOLIDATED BALANCE SHEETS">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaapCashAndCashEquivalentsAtCarryingValue" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CashAndDueFromBanks" xlink:label="loc_us-gaapCashAndDueFromBanks" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapCashAndCashEquivalentsAtCarryingValue" xlink:to="loc_us-gaapCashAndDueFromBanks" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestBearingDepositsInBanks" xlink:label="loc_us-gaapInterestBearingDepositsInBanks" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapCashAndCashEquivalentsAtCarryingValue" xlink:to="loc_us-gaapInterestBearingDepositsInBanks" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="cass-20180930.xsd#cass_FederalFundsSoldAndOtherShortTermInvestments" xlink:label="loc_cassFederalFundsSoldAndOtherShortTermInvestments" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapCashAndCashEquivalentsAtCarryingValue" xlink:to="loc_cassFederalFundsSoldAndOtherShortTermInvestments" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableNetReportedAmount" xlink:label="loc_us-gaapLoansAndLeasesReceivableNetReportedAmount" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome" xlink:label="loc_us-gaapLoansAndLeasesReceivableNetOfDeferredIncome" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLoansAndLeasesReceivableNetReportedAmount" xlink:to="loc_us-gaapLoansAndLeasesReceivableNetOfDeferredIncome" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableAllowance" xlink:label="loc_us-gaapLoansAndLeasesReceivableAllowance" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLoansAndLeasesReceivableNetReportedAmount" xlink:to="loc_us-gaapLoansAndLeasesReceivableAllowance" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_Assets" xlink:label="loc_us-gaapAssets" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesCurrent" xlink:label="loc_us-gaapAvailableForSaleSecuritiesCurrent" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssets" xlink:to="loc_us-gaapAvailableForSaleSecuritiesCurrent" xlink:type="arc" weight="1" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssets" xlink:to="loc_us-gaapCashAndCashEquivalentsAtCarryingValue" xlink:type="arc" weight="1" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssets" xlink:to="loc_us-gaapLoansAndLeasesReceivableNetReportedAmount" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaapPropertyPlantAndEquipmentNet" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssets" xlink:to="loc_us-gaapPropertyPlantAndEquipmentNet" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BankOwnedLifeInsurance" xlink:label="loc_us-gaapBankOwnedLifeInsurance" />
      <link:calculationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssets" xlink:to="loc_us-gaapBankOwnedLifeInsurance" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="cass-20180930.xsd#cass_PaymentsInExcessOfFunding" xlink:label="loc_cassPaymentsInExcessOfFunding" />
      <link:calculationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssets" xlink:to="loc_cassPaymentsInExcessOfFunding" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_Goodwill" xlink:label="loc_us-gaapGoodwill" />
      <link:calculationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssets" xlink:to="loc_us-gaapGoodwill" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:label="loc_us-gaapIntangibleAssetsNetExcludingGoodwill" />
      <link:calculationArc order="8" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssets" xlink:to="loc_us-gaapIntangibleAssetsNetExcludingGoodwill" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherAssets" xlink:label="loc_us-gaapOtherAssets" />
      <link:calculationArc order="9" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssets" xlink:to="loc_us-gaapOtherAssets" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_Deposits" xlink:label="loc_us-gaapDeposits" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NoninterestBearingDepositLiabilities" xlink:label="loc_us-gaapNoninterestBearingDepositLiabilities" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapDeposits" xlink:to="loc_us-gaapNoninterestBearingDepositLiabilities" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestBearingDepositLiabilities" xlink:label="loc_us-gaapInterestBearingDepositLiabilities" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapDeposits" xlink:to="loc_us-gaapInterestBearingDepositLiabilities" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_Liabilities" xlink:label="loc_us-gaapLiabilities" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilities" xlink:to="loc_us-gaapDeposits" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="cass-20180930.xsd#cass_AccountsAndDraftsPayable" xlink:label="loc_cassAccountsAndDraftsPayable" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilities" xlink:to="loc_cassAccountsAndDraftsPayable" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherLiabilities" xlink:label="loc_us-gaapOtherLiabilities" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilities" xlink:to="loc_us-gaapOtherLiabilities" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="loc_us-gaapStockholdersEquity" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PreferredStockValue" xlink:label="loc_us-gaapPreferredStockValue" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapStockholdersEquity" xlink:to="loc_us-gaapPreferredStockValue" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommonStockValue" xlink:label="loc_us-gaapCommonStockValue" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapStockholdersEquity" xlink:to="loc_us-gaapCommonStockValue" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AdditionalPaidInCapitalCommonStock" xlink:label="loc_us-gaapAdditionalPaidInCapitalCommonStock" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapStockholdersEquity" xlink:to="loc_us-gaapAdditionalPaidInCapitalCommonStock" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="loc_us-gaapRetainedEarningsAccumulatedDeficit" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapStockholdersEquity" xlink:to="loc_us-gaapRetainedEarningsAccumulatedDeficit" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TreasuryStockValue" xlink:label="loc_us-gaapTreasuryStockValue" />
      <link:calculationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapStockholdersEquity" xlink:to="loc_us-gaapTreasuryStockValue" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:label="loc_us-gaapAccumulatedOtherComprehensiveIncomeLossNetOfTax" />
      <link:calculationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapStockholdersEquity" xlink:to="loc_us-gaapAccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="loc_us-gaapLiabilitiesAndStockholdersEquity" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilitiesAndStockholdersEquity" xlink:to="loc_us-gaapLiabilities" xlink:type="arc" weight="1" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilitiesAndStockholdersEquity" xlink:to="loc_us-gaapStockholdersEquity" xlink:type="arc" weight="1" />
    </link:calculationLink>
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-cbsp" xlink:title="00000003 - Statement - CONSOLIDATED BALANCE SHEETS (Parenthetical)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-csoi" xlink:title="00000004 - Statement - CONSOLIDATED STATEMENTS OF INCOME (Unaudited)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NoninterestIncome" xlink:label="loc_us-gaapNoninterestIncome" />
      <link:loc xlink:type="locator" xlink:href="cass-20180930.xsd#cass_InformationServicesPaymentAndProcessingRevenue" xlink:label="loc_cassInformationServicesPaymentAndProcessingRevenue" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNoninterestIncome" xlink:to="loc_cassInformationServicesPaymentAndProcessingRevenue" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="cass-20180930.xsd#cass_BankServiceFees" xlink:label="loc_cassBankServiceFees" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNoninterestIncome" xlink:to="loc_cassBankServiceFees" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtAndEquitySecuritiesGainLoss" xlink:label="loc_us-gaapDebtAndEquitySecuritiesGainLoss" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNoninterestIncome" xlink:to="loc_us-gaapDebtAndEquitySecuritiesGainLoss" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NoninterestIncomeOther" xlink:label="loc_us-gaapNoninterestIncomeOther" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNoninterestIncome" xlink:to="loc_us-gaapNoninterestIncomeOther" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestAndDividendIncomeOperating" xlink:label="loc_us-gaapInterestAndDividendIncomeOperating" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestAndFeeIncomeLoansAndLeases" xlink:label="loc_us-gaapInterestAndFeeIncomeLoansAndLeases" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapInterestAndDividendIncomeOperating" xlink:to="loc_us-gaapInterestAndFeeIncomeLoansAndLeases" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestIncomeSecuritiesTaxable" xlink:label="loc_us-gaapInterestIncomeSecuritiesTaxable" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapInterestAndDividendIncomeOperating" xlink:to="loc_us-gaapInterestIncomeSecuritiesTaxable" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestIncomeSecuritiesTaxExempt" xlink:label="loc_us-gaapInterestIncomeSecuritiesTaxExempt" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapInterestAndDividendIncomeOperating" xlink:to="loc_us-gaapInterestIncomeSecuritiesTaxExempt" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="cass-20180930.xsd#cass_InterestOnFederalFundsSoldAndOtherShortTermInvestments" xlink:label="loc_cassInterestOnFederalFundsSoldAndOtherShortTermInvestments" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapInterestAndDividendIncomeOperating" xlink:to="loc_cassInterestOnFederalFundsSoldAndOtherShortTermInvestments" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestIncomeExpenseNet" xlink:label="loc_us-gaapInterestIncomeExpenseNet" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapInterestIncomeExpenseNet" xlink:to="loc_us-gaapInterestAndDividendIncomeOperating" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestExpenseDeposits" xlink:label="loc_us-gaapInterestExpenseDeposits" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapInterestIncomeExpenseNet" xlink:to="loc_us-gaapInterestExpenseDeposits" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss" xlink:label="loc_us-gaapInterestIncomeExpenseAfterProvisionForLoanLoss" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapInterestIncomeExpenseAfterProvisionForLoanLoss" xlink:to="loc_us-gaapInterestIncomeExpenseNet" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ProvisionForLoanLossesExpensed" xlink:label="loc_us-gaapProvisionForLoanLossesExpensed" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapInterestIncomeExpenseAfterProvisionForLoanLoss" xlink:to="loc_us-gaapProvisionForLoanLossesExpensed" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_Revenues" xlink:label="loc_us-gaapRevenues" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapRevenues" xlink:to="loc_us-gaapNoninterestIncome" xlink:type="arc" weight="1" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapRevenues" xlink:to="loc_us-gaapInterestIncomeExpenseAfterProvisionForLoanLoss" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NoninterestExpense" xlink:label="loc_us-gaapNoninterestExpense" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LaborAndRelatedExpense" xlink:label="loc_us-gaapLaborAndRelatedExpense" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNoninterestExpense" xlink:to="loc_us-gaapLaborAndRelatedExpense" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OccupancyNet" xlink:label="loc_us-gaapOccupancyNet" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNoninterestExpense" xlink:to="loc_us-gaapOccupancyNet" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EquipmentExpense" xlink:label="loc_us-gaapEquipmentExpense" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNoninterestExpense" xlink:to="loc_us-gaapEquipmentExpense" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AmortizationOfIntangibleAssets" xlink:label="loc_us-gaapAmortizationOfIntangibleAssets" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNoninterestExpense" xlink:to="loc_us-gaapAmortizationOfIntangibleAssets" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherNoninterestExpense" xlink:label="loc_us-gaapOtherNoninterestExpense" />
      <link:calculationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNoninterestExpense" xlink:to="loc_us-gaapOtherNoninterestExpense" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaapNetIncomeLoss" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:label="loc_us-gaapIncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetIncomeLoss" xlink:to="loc_us-gaapIncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="loc_us-gaapIncomeTaxExpenseBenefit" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetIncomeLoss" xlink:to="loc_us-gaapIncomeTaxExpenseBenefit" xlink:type="arc" weight="-1" />
    </link:calculationLink>
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/ConsolidatedStatementsOfComprehensiveIncome" xlink:title="00000005 - Statement - CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTax" xlink:label="loc_us-gaapComprehensiveIncomeNetOfTax" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaapNetIncomeLoss" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapComprehensiveIncomeNetOfTax" xlink:to="loc_us-gaapNetIncomeLoss" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax" xlink:label="loc_us-gaapOtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapComprehensiveIncomeNetOfTax" xlink:to="loc_us-gaapOtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax" xlink:label="loc_us-gaapOtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapComprehensiveIncomeNetOfTax" xlink:to="loc_us-gaapOtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax" xlink:label="loc_us-gaapOtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapComprehensiveIncomeNetOfTax" xlink:to="loc_us-gaapOtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax" xlink:label="loc_us-gaapOtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax" />
      <link:calculationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapComprehensiveIncomeNetOfTax" xlink:to="loc_us-gaapOtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax" xlink:label="loc_us-gaapOtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax" />
      <link:calculationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapComprehensiveIncomeNetOfTax" xlink:to="loc_us-gaapOtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax" xlink:type="arc" weight="1" />
    </link:calculationLink>
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/ConsolidatedStatementsOfCashFlows" xlink:title="00000006 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DepreciationAmortizationAndAccretionNet" xlink:label="loc_us-gaapDepreciationAmortizationAndAccretionNet" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapDepreciationAmortizationAndAccretionNet" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtAndEquitySecuritiesGainLoss" xlink:label="loc_us-gaapDebtAndEquitySecuritiesGainLoss" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapDebtAndEquitySecuritiesGainLoss" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensation" xlink:label="loc_us-gaapShareBasedCompensation" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapShareBasedCompensation" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable" xlink:label="loc_us-gaapIncreaseDecreaseInAccruedIncomeTaxesPayable" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapIncreaseDecreaseInAccruedIncomeTaxesPayable" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncreaseDecreaseInPensionPlanObligations" xlink:label="loc_us-gaapIncreaseDecreaseInPensionPlanObligations" />
      <link:calculationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapIncreaseDecreaseInPensionPlanObligations" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivities" xlink:label="loc_us-gaapAdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivities" />
      <link:calculationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapAdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivities" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaapNetIncomeLoss" />
      <link:calculationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapNetIncomeLoss" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsReceivable" xlink:label="loc_us-gaapIncreaseDecreaseInAccountsReceivable" />
      <link:calculationArc order="8" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapIncreaseDecreaseInAccountsReceivable" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:label="loc_us-gaapNetCashProvidedByUsedInInvestingActivities" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ProceedsFromSaleOfAvailableForSaleSecurities" xlink:label="loc_us-gaapProceedsFromSaleOfAvailableForSaleSecurities" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInInvestingActivities" xlink:to="loc_us-gaapProceedsFromSaleOfAvailableForSaleSecurities" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities" xlink:label="loc_us-gaapProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInInvestingActivities" xlink:to="loc_us-gaapProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsToAcquireAvailableForSaleSecurities" xlink:label="loc_us-gaapPaymentsToAcquireAvailableForSaleSecurities" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInInvestingActivities" xlink:to="loc_us-gaapPaymentsToAcquireAvailableForSaleSecurities" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsForProceedsFromLoansAndLeases" xlink:label="loc_us-gaapPaymentsForProceedsFromLoansAndLeases" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInInvestingActivities" xlink:to="loc_us-gaapPaymentsForProceedsFromLoansAndLeases" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="cass-20180930.xsd#cass_IncreaseDecreaseInPaymentsInExcessOfFunding" xlink:label="loc_cassIncreaseDecreaseInPaymentsInExcessOfFunding" />
      <link:calculationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInInvestingActivities" xlink:to="loc_cassIncreaseDecreaseInPaymentsInExcessOfFunding" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:label="loc_us-gaapPaymentsToAcquirePropertyPlantAndEquipment" />
      <link:calculationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInInvestingActivities" xlink:to="loc_us-gaapPaymentsToAcquirePropertyPlantAndEquipment" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:label="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" />
      <link:loc xlink:type="locator" xlink:href="cass-20180930.xsd#cass_IncreaseDecreaseInNonInterestBearingDemandDeposits" xlink:label="loc_cassIncreaseDecreaseInNonInterestBearingDemandDeposits" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_cassIncreaseDecreaseInNonInterestBearingDemandDeposits" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="cass-20180930.xsd#cass_IncreaseDecreaseInInterestBearingDemandAndSavingsDeposits" xlink:label="loc_cassIncreaseDecreaseInInterestBearingDemandAndSavingsDeposits" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_cassIncreaseDecreaseInInterestBearingDemandAndSavingsDeposits" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncreaseDecreaseInTimeDeposits" xlink:label="loc_us-gaapIncreaseDecreaseInTimeDeposits" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_us-gaapIncreaseDecreaseInTimeDeposits" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="cass-20180930.xsd#cass_IncreaseDecreaseInAccountsAndDraftsPayable" xlink:label="loc_cassIncreaseDecreaseInAccountsAndDraftsPayable" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_cassIncreaseDecreaseInAccountsAndDraftsPayable" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsOfDividendsCommonStock" xlink:label="loc_us-gaapPaymentsOfDividendsCommonStock" />
      <link:calculationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_us-gaapPaymentsOfDividendsCommonStock" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsForRepurchaseOfCommonStock" xlink:label="loc_us-gaapPaymentsForRepurchaseOfCommonStock" />
      <link:calculationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_us-gaapPaymentsForRepurchaseOfCommonStock" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ProceedsFromPaymentsForOtherFinancingActivities" xlink:label="loc_us-gaapProceedsFromPaymentsForOtherFinancingActivities" />
      <link:calculationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_us-gaapProceedsFromPaymentsForOtherFinancingActivities" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease" xlink:label="loc_us-gaapCashAndCashEquivalentsPeriodIncreaseDecrease" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapCashAndCashEquivalentsPeriodIncreaseDecrease" xlink:to="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:type="arc" weight="1" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapCashAndCashEquivalentsPeriodIncreaseDecrease" xlink:to="loc_us-gaapNetCashProvidedByUsedInInvestingActivities" xlink:type="arc" weight="1" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapCashAndCashEquivalentsPeriodIncreaseDecrease" xlink:to="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:type="arc" weight="1" />
    </link:calculationLink>
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-bop" xlink:title="00000007 - Disclosure - Basis of Presentation" />
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-ia" xlink:title="00000008 - Disclosure - Intangible Assets" />
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-eps" xlink:title="00000009 - Disclosure - Earnings Per Share" />
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-sr" xlink:title="00000010 - Disclosure - Stock Repurchases" />
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-isi" xlink:title="00000011 - Disclosure - Industry Segment Information" />
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-lbt" xlink:title="00000012 - Disclosure - Loans by Type" />
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-cac" xlink:title="00000013 - Disclosure - Commitments and Contingencies" />
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-sc" xlink:title="00000014 - Disclosure - Stock-Based Compensation" />
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-dpp" xlink:title="00000015 - Disclosure - Defined Pension Plans" />
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-it" xlink:title="00000016 - Disclosure - Income Taxes" />
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-iis" xlink:title="00000017 - Disclosure - Investment in Securities" />
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-fvofi" xlink:title="00000018 - Disclosure - Fair Value of Financial Instruments" />
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-se" xlink:title="00000019 - Disclosure - Subsequent Events" />
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-iat" xlink:title="00000020 - Disclosure - Intangible Assets (Tables)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-epst" xlink:title="00000021 - Disclosure - Earnings Per Share (Tables)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-isit" xlink:title="00000022 - Disclosure - Industry Segment Information (Tables)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-lbtt" xlink:title="00000023 - Disclosure - Loans by Type (Tables)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-cact" xlink:title="00000024 - Disclosure - Commitments and Contingencies (Tables)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-sct" xlink:title="00000025 - Disclosure - Stock-Based Compensation (Tables)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-dppt" xlink:title="00000026 - Disclosure - Defined Pension Plans (Tables)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-iist" xlink:title="00000027 - Disclosure - Investment in Securities (Tables)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-fvofit" xlink:title="00000028 - Disclosure - Fair Value of Financial Instruments (Tables)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-iand" xlink:title="00000029 - Disclosure - Intangible Assets (Narrative) (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-iasociad" xlink:title="00000030 - Disclosure - Intangible Assets (Schedule of Company's Intangible Assets) (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-epsd" xlink:title="00000031 - Disclosure - Earnings Per Share (Details)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:label="loc_us-gaapWeightedAverageNumberOfDilutedSharesOutstanding" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:label="loc_us-gaapWeightedAverageNumberOfSharesOutstandingBasic" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapWeightedAverageNumberOfDilutedSharesOutstanding" xlink:to="loc_us-gaapWeightedAverageNumberOfSharesOutstandingBasic" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment" xlink:label="loc_us-gaapWeightedAverageNumberDilutedSharesOutstandingAdjustment" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapWeightedAverageNumberOfDilutedSharesOutstanding" xlink:to="loc_us-gaapWeightedAverageNumberDilutedSharesOutstandingAdjustment" xlink:type="arc" weight="1" />
    </link:calculationLink>
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-srd" xlink:title="00000032 - Disclosure - Stock Repurchases (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-isid" xlink:title="00000033 - Disclosure - Industry Segment Information (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-lbtsolcd" xlink:title="00000034 - Disclosure - Loans by Type (Summary of Loan Categories) (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-lbtsoaolblcd" xlink:title="00000035 - Disclosure - Loans by Type (Schedule of the Aging of Loans by Loan Categories) (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-lbtsoceolpd" xlink:title="00000036 - Disclosure - Loans by Type (Schedule of the Credit Exposure of the Loan Portfolio) (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-lbtsoaflld" xlink:title="00000037 - Disclosure - Loans by Type (Summary of Allowance for Loan Losses) (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-cacnd" xlink:title="00000038 - Disclosure - Commitments and Contingencies (Narrative) (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-cacsocccod" xlink:title="00000039 - Disclosure - Commitments and Contingencies (Summary of Company's Contractual Cash Obligations) (Details)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDue" xlink:label="loc_us-gaapOperatingLeasesFutureMinimumPaymentsDue" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent" xlink:label="loc_us-gaapOperatingLeasesFutureMinimumPaymentsDueCurrent" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapOperatingLeasesFutureMinimumPaymentsDue" xlink:to="loc_us-gaapOperatingLeasesFutureMinimumPaymentsDueCurrent" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears" xlink:label="loc_us-gaapOperatingLeasesFutureMinimumPaymentsDueInThreeYears" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapOperatingLeasesFutureMinimumPaymentsDue" xlink:to="loc_us-gaapOperatingLeasesFutureMinimumPaymentsDueInThreeYears" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears" xlink:label="loc_us-gaapOperatingLeasesFutureMinimumPaymentsDueInFiveYears" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapOperatingLeasesFutureMinimumPaymentsDue" xlink:to="loc_us-gaapOperatingLeasesFutureMinimumPaymentsDueInFiveYears" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter" xlink:label="loc_us-gaapOperatingLeasesFutureMinimumPaymentsDueThereafter" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapOperatingLeasesFutureMinimumPaymentsDue" xlink:to="loc_us-gaapOperatingLeasesFutureMinimumPaymentsDueThereafter" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TimeDeposits" xlink:label="loc_us-gaapTimeDeposits" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TimeDepositMaturitiesYearOne" xlink:label="loc_us-gaapTimeDepositMaturitiesYearOne" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapTimeDeposits" xlink:to="loc_us-gaapTimeDepositMaturitiesYearOne" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TimeDepositMaturitiesYearThree" xlink:label="loc_us-gaapTimeDepositMaturitiesYearThree" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapTimeDeposits" xlink:to="loc_us-gaapTimeDepositMaturitiesYearThree" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TimeDepositMaturitiesYearFive" xlink:label="loc_us-gaapTimeDepositMaturitiesYearFive" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapTimeDeposits" xlink:to="loc_us-gaapTimeDepositMaturitiesYearFive" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TimeDepositMaturitiesAfterYearFive" xlink:label="loc_us-gaapTimeDepositMaturitiesAfterYearFive" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapTimeDeposits" xlink:to="loc_us-gaapTimeDepositMaturitiesAfterYearFive" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherCommitment" xlink:label="loc_us-gaapOtherCommitment" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherCommitmentDueInNextTwelveMonths" xlink:label="loc_us-gaapOtherCommitmentDueInNextTwelveMonths" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapOtherCommitment" xlink:to="loc_us-gaapOtherCommitmentDueInNextTwelveMonths" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherCommitmentDueInThirdYear" xlink:label="loc_us-gaapOtherCommitmentDueInThirdYear" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapOtherCommitment" xlink:to="loc_us-gaapOtherCommitmentDueInThirdYear" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherCommitmentDueInFifthYear" xlink:label="loc_us-gaapOtherCommitmentDueInFifthYear" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapOtherCommitment" xlink:to="loc_us-gaapOtherCommitmentDueInFifthYear" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherCommitmentDueAfterFifthYear" xlink:label="loc_us-gaapOtherCommitmentDueAfterFifthYear" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapOtherCommitment" xlink:to="loc_us-gaapOtherCommitmentDueAfterFifthYear" xlink:type="arc" weight="1" />
    </link:calculationLink>
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-scnd" xlink:title="00000040 - Disclosure - Stock-Based Compensation (Narrative) (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-scsorsad" xlink:title="00000041 - Disclosure - Stock-Based Compensation (Summary of Restricted Stock Activity) (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-scsocsad" xlink:title="00000042 - Disclosure - Stock-Based Compensation (Summary of Company's SARs Activity) (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-dppnd" xlink:title="00000043 - Disclosure - Defined Pension Plans (Narrative) (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-dppsonppcd" xlink:title="00000044 - Disclosure - Defined Pension Plans (Schedule of Net Periodic Pension Costs) (Details)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" xlink:label="loc_us-gaapDefinedBenefitPlanNetPeriodicBenefitCost" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DefinedBenefitPlanServiceCost" xlink:label="loc_us-gaapDefinedBenefitPlanServiceCost" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapDefinedBenefitPlanNetPeriodicBenefitCost" xlink:to="loc_us-gaapDefinedBenefitPlanServiceCost" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DefinedBenefitPlanInterestCost" xlink:label="loc_us-gaapDefinedBenefitPlanInterestCost" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapDefinedBenefitPlanNetPeriodicBenefitCost" xlink:to="loc_us-gaapDefinedBenefitPlanInterestCost" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets" xlink:label="loc_us-gaapDefinedBenefitPlanExpectedReturnOnPlanAssets" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapDefinedBenefitPlanNetPeriodicBenefitCost" xlink:to="loc_us-gaapDefinedBenefitPlanExpectedReturnOnPlanAssets" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit" xlink:label="loc_us-gaapDefinedBenefitPlanAmortizationOfPriorServiceCostCredit" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapDefinedBenefitPlanNetPeriodicBenefitCost" xlink:to="loc_us-gaapDefinedBenefitPlanAmortizationOfPriorServiceCostCredit" xlink:type="arc" weight="1" />
    </link:calculationLink>
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/IncomeTaxesDetails" xlink:title="00000045 - Disclosure - Income Taxes (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/InvestmentInSecuritiesNarrativeDetails" xlink:title="00000046 - Disclosure - Investment in Securities (Narrative) (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-iissoisd" xlink:title="00000047 - Disclosure - Investment in Securities (Schedule of Investment Securities) (Details)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesAmortizedCost" xlink:label="loc_us-gaapAvailableForSaleSecuritiesAmortizedCost" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecurities" xlink:label="loc_us-gaapAvailableForSaleSecurities" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAvailableForSaleSecuritiesAmortizedCost" xlink:to="loc_us-gaapAvailableForSaleSecurities" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedGainBeforeTax" xlink:label="loc_us-gaapAvailableForSaleSecuritiesAccumulatedGrossUnrealizedGainBeforeTax" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAvailableForSaleSecuritiesAmortizedCost" xlink:to="loc_us-gaapAvailableForSaleSecuritiesAccumulatedGrossUnrealizedGainBeforeTax" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax" xlink:label="loc_us-gaapAvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAvailableForSaleSecuritiesAmortizedCost" xlink:to="loc_us-gaapAvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax" xlink:type="arc" weight="1" />
    </link:calculationLink>
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-iissofvoswuld" xlink:title="00000048 - Disclosure - Investment in Securities (Schedule of the Fair Values of Securities with Unrealized Losses) (Details)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue" xlink:label="loc_us-gaapAvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue" xlink:label="loc_us-gaapAvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue" xlink:to="loc_us-gaapAvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue" xlink:label="loc_us-gaapAvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue" xlink:to="loc_us-gaapAvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss" xlink:label="loc_us-gaapAvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss" xlink:label="loc_us-gaapAvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss" xlink:to="loc_us-gaapAvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss" xlink:label="loc_us-gaapAvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss" xlink:to="loc_us-gaapAvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss" xlink:type="arc" weight="1" />
    </link:calculationLink>
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-iissoacafvoisd" xlink:title="00000049 - Disclosure - Investment in Securities (Schedule of Amortized Cost and Fair Value of Investment Securities) (Details)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis" xlink:label="loc_us-gaapAvailableForSaleDebtSecuritiesAmortizedCostBasis" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost" xlink:label="loc_us-gaapAvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAvailableForSaleDebtSecuritiesAmortizedCostBasis" xlink:to="loc_us-gaapAvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost" xlink:label="loc_us-gaapAvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAvailableForSaleDebtSecuritiesAmortizedCostBasis" xlink:to="loc_us-gaapAvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost" xlink:label="loc_us-gaapAvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAvailableForSaleDebtSecuritiesAmortizedCostBasis" xlink:to="loc_us-gaapAvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost" xlink:label="loc_us-gaapAvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAvailableForSaleDebtSecuritiesAmortizedCostBasis" xlink:to="loc_us-gaapAvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecurities" xlink:label="loc_us-gaapAvailableForSaleSecurities" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue" xlink:label="loc_us-gaapAvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAvailableForSaleSecurities" xlink:to="loc_us-gaapAvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue" xlink:label="loc_us-gaapAvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAvailableForSaleSecurities" xlink:to="loc_us-gaapAvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue" xlink:label="loc_us-gaapAvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAvailableForSaleSecurities" xlink:to="loc_us-gaapAvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue" xlink:label="loc_us-gaapAvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAvailableForSaleSecurities" xlink:to="loc_us-gaapAvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue" xlink:type="arc" weight="1" />
    </link:calculationLink>
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-fvofid" xlink:title="00000050 - Disclosure - Fair Value of Financial Instruments (Details)">
      <link:loc xlink:type="locator" xlink:href="cass-20180930.xsd#cass_AssetsCarryingAmount" xlink:label="loc_cassAssetsCarryingAmount" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaapCashAndCashEquivalentsAtCarryingValue" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_cassAssetsCarryingAmount" xlink:to="loc_us-gaapCashAndCashEquivalentsAtCarryingValue" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecurities" xlink:label="loc_us-gaapAvailableForSaleSecurities" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_cassAssetsCarryingAmount" xlink:to="loc_us-gaapAvailableForSaleSecurities" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableNetReportedAmount" xlink:label="loc_us-gaapLoansAndLeasesReceivableNetReportedAmount" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_cassAssetsCarryingAmount" xlink:to="loc_us-gaapLoansAndLeasesReceivableNetReportedAmount" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestReceivable" xlink:label="loc_us-gaapInterestReceivable" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_cassAssetsCarryingAmount" xlink:to="loc_us-gaapInterestReceivable" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AssetsFairValueDisclosure" xlink:label="loc_us-gaapAssetsFairValueDisclosure" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InvestmentsFairValueDisclosure" xlink:label="loc_us-gaapInvestmentsFairValueDisclosure" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssetsFairValueDisclosure" xlink:to="loc_us-gaapInvestmentsFairValueDisclosure" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CashAndCashEquivalentsFairValueDisclosure" xlink:label="loc_us-gaapCashAndCashEquivalentsFairValueDisclosure" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssetsFairValueDisclosure" xlink:to="loc_us-gaapCashAndCashEquivalentsFairValueDisclosure" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansReceivableFairValueDisclosure" xlink:label="loc_us-gaapLoansReceivableFairValueDisclosure" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssetsFairValueDisclosure" xlink:to="loc_us-gaapLoansReceivableFairValueDisclosure" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccountsReceivableFairValueDisclosure" xlink:label="loc_us-gaapAccountsReceivableFairValueDisclosure" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssetsFairValueDisclosure" xlink:to="loc_us-gaapAccountsReceivableFairValueDisclosure" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="cass-20180930.xsd#cass_LiabilitiesCarryingValue" xlink:label="loc_cassLiabilitiesCarryingValue" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_Deposits" xlink:label="loc_us-gaapDeposits" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_cassLiabilitiesCarryingValue" xlink:to="loc_us-gaapDeposits" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="cass-20180930.xsd#cass_AccountAndDraftsPayable" xlink:label="loc_cassAccountAndDraftsPayable" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_cassLiabilitiesCarryingValue" xlink:to="loc_cassAccountAndDraftsPayable" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestPayableCurrentAndNoncurrent" xlink:label="loc_us-gaapInterestPayableCurrentAndNoncurrent" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_cassLiabilitiesCarryingValue" xlink:to="loc_us-gaapInterestPayableCurrentAndNoncurrent" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LiabilitiesFairValueDisclosure" xlink:label="loc_us-gaapLiabilitiesFairValueDisclosure" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DepositsFairValueDisclosure" xlink:label="loc_us-gaapDepositsFairValueDisclosure" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilitiesFairValueDisclosure" xlink:to="loc_us-gaapDepositsFairValueDisclosure" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="cass-20180930.xsd#cass_AccountsAndDraftsPayableFairValueDisclosure" xlink:label="loc_cassAccountsAndDraftsPayableFairValueDisclosure" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilitiesFairValueDisclosure" xlink:to="loc_cassAccountsAndDraftsPayableFairValueDisclosure" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccruedLiabilitiesFairValueDisclosure" xlink:label="loc_us-gaapAccruedLiabilitiesFairValueDisclosure" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilitiesFairValueDisclosure" xlink:to="loc_us-gaapAccruedLiabilitiesFairValueDisclosure" xlink:type="arc" weight="1" />
    </link:calculationLink>
    <link:calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/SubsequentEventsDetails" xlink:title="00000051 - Disclosure -  Subsequent Events (Details)" />
</link:linkbase>
