<?xml version="1.0" encoding="UTF-8"?>
<schema attributeFormDefault="unqualified" elementFormDefault="qualified" xmlns="http://www.w3.org/2001/XMLSchema" xmlns:country="http://xbrl.sec.gov/country/2020-01-31" xmlns:currency="http://xbrl.sec.gov/currency/2020-01-31" xmlns:dei="http://xbrl.sec.gov/dei/2019-01-31" xmlns:exch="http://xbrl.sec.gov/exch/2020-01-31" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:nonnum="http://www.xbrl.org/dtr/type/non-numeric" xmlns:num="http://www.xbrl.org/dtr/type/numeric" xmlns:stpr="http://xbrl.sec.gov/stpr/2018-01-31" xmlns:us-gaap="http://fasb.org/us-gaap/2020-01-31" xmlns:us-roles="http://fasb.org/us-roles/2020-01-31" xmlns:us-types="http://fasb.org/us-types/2019-01-31" xmlns:xbrldi="http://xbrl.org/2006/xbrldi" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:naics="http://xbrl.sec.gov/naics/2017-01-31" xmlns:srt="http://fasb.org/srt/2020-01-31" xmlns:srt-types="http://fasb.org/srt-types/2020-01-31" targetNamespace="http://cassinfo.com/20200331" xmlns:cass="http://cassinfo.com/20200331">
  <!-- XBRL Document Created with XML Edge from P3 Data Systems -->
  <annotation>
    <appinfo>
      <link:linkbaseRef xlink:type="simple" xlink:href="cass-20200331_cal.xml" xlink:role="http://www.xbrl.org/2003/role/calculationLinkbaseRef" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase"/>
      <link:linkbaseRef xlink:type="simple" xlink:href="cass-20200331_def.xml" xlink:role="http://www.xbrl.org/2003/role/definitionLinkbaseRef" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase"/>
      <link:linkbaseRef xlink:type="simple" xlink:href="cass-20200331_lab.xml" xlink:role="http://www.xbrl.org/2003/role/labelLinkbaseRef" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase"/>
      <link:linkbaseRef xlink:type="simple" xlink:href="cass-20200331_pre.xml" xlink:role="http://www.xbrl.org/2003/role/presentationLinkbaseRef" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase"/>
      <link:roleType roleURI="http://cassinfo.com/role/cass-daei" id="cass-daei">
        <link:definition>00010 - Document - Document and Entity Information</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/cass-cbs" id="cass-cbs">
        <link:definition>00020 - Statement - CONSOLIDATED BALANCE SHEETS</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/cass-cbsp" id="cass-cbsp">
        <link:definition>00030 - Statement - CONSOLIDATED BALANCE SHEETS (Parenthetical)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/cass-csoi" id="cass-csoi">
        <link:definition>00040 - Statement - CONSOLIDATED STATEMENTS OF INCOME (Unaudited)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/ConsolidatedStatementsOfComprehensiveIncome" id="ConsolidatedStatementsOfComprehensiveIncome">
        <link:definition>00050 - Statement - CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/ConsolidatedStatementsOfCashFlows" id="ConsolidatedStatementsOfCashFlows">
        <link:definition>00060 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/ConsolidatedStatementsOfShareholdersEquity" id="ConsolidatedStatementsOfShareholdersEquity">
        <link:definition>00070 - Statement - CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (Unaudited)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/ConsolidatedStatementsOfShareholdersEquityParenthetical" id="ConsolidatedStatementsOfShareholdersEquityParenthetical">
        <link:definition>00080 - Statement - CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (Parenthetical)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/cass-bop" id="cass-bop">
        <link:definition>00090 - Disclosure - Basis of Presentation</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/cass-ia" id="cass-ia">
        <link:definition>00100 - Disclosure - Intangible Assets</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/cass-eps" id="cass-eps">
        <link:definition>00110 - Disclosure - Earnings Per Share</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/cass-sr" id="cass-sr">
        <link:definition>00120 - Disclosure - Stock Repurchases</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/cass-isi" id="cass-isi">
        <link:definition>00130 - Disclosure - Industry Segment Information</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/cass-lbt" id="cass-lbt">
        <link:definition>00140 - Disclosure - Loans by Type</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/cass-cac" id="cass-cac">
        <link:definition>00150 - Disclosure - Commitments and Contingencies</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/cass-sc" id="cass-sc">
        <link:definition>00160 - Disclosure - Stock-Based Compensation</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/cass-dpp" id="cass-dpp">
        <link:definition>00170 - Disclosure - Defined Pension Plans</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/cass-it" id="cass-it">
        <link:definition>00180 - Disclosure - Income Taxes</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/cass-iis" id="cass-iis">
        <link:definition>00190 - Disclosure - Investment in Securities</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/cass-fvofi" id="cass-fvofi">
        <link:definition>00200 - Disclosure - Fair Value of Financial Instruments</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/RevenueFromContractsWithCustomers" id="RevenueFromContractsWithCustomers">
        <link:definition>00210 - Disclosure - Revenue from Contracts with Customers</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/Leases" id="Leases">
        <link:definition>00220 - Disclosure - Leases</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/cass-se" id="cass-se">
        <link:definition>00230 - Disclosure - Subsequent Events</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/cass-iat" id="cass-iat">
        <link:definition>00240 - Disclosure - Intangible Assets (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/cass-epst" id="cass-epst">
        <link:definition>00250 - Disclosure - Earnings Per Share (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/cass-isit" id="cass-isit">
        <link:definition>00260 - Disclosure - Industry Segment Information (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/cass-lbtt" id="cass-lbtt">
        <link:definition>00270 - Disclosure - Loans by Type (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/cass-cact" id="cass-cact">
        <link:definition>00280 - Disclosure - Commitments and Contingencies (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/cass-sct" id="cass-sct">
        <link:definition>00290 - Disclosure - Stock-Based Compensation (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/cass-dppt" id="cass-dppt">
        <link:definition>00300 - Disclosure - Defined Pension Plans (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/cass-iist" id="cass-iist">
        <link:definition>00310 - Disclosure - Investment in Securities (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/cass-fvofit" id="cass-fvofit">
        <link:definition>00320 - Disclosure - Fair Value of Financial Instruments (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/RevenueFromContractsWithCustomersTables" id="RevenueFromContractsWithCustomersTables">
        <link:definition>00330 - Disclosure - Revenue from Contracts with Customers (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/LeasesTables" id="LeasesTables">
        <link:definition>00340 - Disclosure - Leases (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/cass-iand" id="cass-iand">
        <link:definition>00350 - Disclosure - Intangible Assets (Narrative) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/cass-iasociad" id="cass-iasociad">
        <link:definition>00360 - Disclosure - Intangible Assets (Schedule of Company's Intangible Assets) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/cass-epsd" id="cass-epsd">
        <link:definition>00370 - Disclosure - Earnings Per Share (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/cass-srd" id="cass-srd">
        <link:definition>00380 - Disclosure - Stock Repurchases (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/cass-isid" id="cass-isid">
        <link:definition>00390 - Disclosure - Industry Segment Information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/cass-lbtsolcd" id="cass-lbtsolcd">
        <link:definition>00400 - Disclosure - Loans by Type (Summary of Loan Categories) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/cass-lbtsoaolblcd" id="cass-lbtsoaolblcd">
        <link:definition>00410 - Disclosure - Loans by Type (Schedule of the Aging of Loans by Loan Categories) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/cass-lbtsoceolpd" id="cass-lbtsoceolpd">
        <link:definition>00420 - Disclosure - Loans by Type (Schedule of the Credit Exposure of the Loan Portfolio) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/cass-lbtsoaflld" id="cass-lbtsoaflld">
        <link:definition>00430 - Disclosure - Loans by Type (Summary of Allowance for Loan Losses) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/CommitmentsAndContingenciesNarrativeDetails" id="CommitmentsAndContingenciesNarrativeDetails">
        <link:definition>00440 - Disclosure - Commitments and Contingencies (Narrative) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/cass-cacsocccod" id="cass-cacsocccod">
        <link:definition>00450 - Disclosure - Commitments and Contingencies (Summary of Company's Contractual Cash Obligations) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/Stock-basedCompensationNarrativeDetails" id="Stock-basedCompensationNarrativeDetails">
        <link:definition>00460 - Disclosure - Stock-Based Compensation (Narrative) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/Stock-basedCompensationSummaryOfRestrictedStockActivityDetails" id="Stock-basedCompensationSummaryOfRestrictedStockActivityDetails">
        <link:definition>00470 - Disclosure - Stock-Based Compensation (Summary of Restricted Stock Activity) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/Stock-basedCompensationSummaryOfPbrsActivityDetails" id="Stock-basedCompensationSummaryOfPbrsActivityDetails">
        <link:definition>00480 - Disclosure - Stock-Based Compensation (Summary of PBRS Activity) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/Stock-basedCompensationSummaryOfCompanysSarsActivityDetails" id="Stock-basedCompensationSummaryOfCompanysSarsActivityDetails">
        <link:definition>00490 - Disclosure - Stock-Based Compensation (Summary of Company's SARs Activity) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/DefinedPensionPlansNarrativeDetails" id="DefinedPensionPlansNarrativeDetails">
        <link:definition>00500 - Disclosure - Defined Pension Plans (Narrative) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/DefinedPensionPlansScheduleOfNetPeriodicPensionCostsDetails" id="DefinedPensionPlansScheduleOfNetPeriodicPensionCostsDetails">
        <link:definition>00510 - Disclosure - Defined Pension Plans (Schedule of Net Periodic Pension Costs) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/IncomeTaxesDetails" id="IncomeTaxesDetails">
        <link:definition>00520 - Disclosure - Income Taxes (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/InvestmentInSecuritiesNarrativeDetails" id="InvestmentInSecuritiesNarrativeDetails">
        <link:definition>00530 - Disclosure - Investment in Securities (Narrative) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/InvestmentInSecuritiesScheduleOfInvestmentSecuritiesDetails" id="InvestmentInSecuritiesScheduleOfInvestmentSecuritiesDetails">
        <link:definition>00540 - Disclosure - Investment in Securities (Schedule of Investment Securities) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/InvestmentInSecuritiesScheduleOfFairValuesOfSecuritiesWithUnrealizedLossesDetails" id="InvestmentInSecuritiesScheduleOfFairValuesOfSecuritiesWithUnrealizedLossesDetails">
        <link:definition>00550 - Disclosure - Investment in Securities (Schedule of the Fair Values of Securities with Unrealized Losses) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/InvestmentInSecuritiesScheduleOfAmortizedCostAndFairValueOfInvestmentSecuritiesDetails" id="InvestmentInSecuritiesScheduleOfAmortizedCostAndFairValueOfInvestmentSecuritiesDetails">
        <link:definition>00560 - Disclosure - Investment in Securities (Schedule of Amortized Cost and Fair Value of Investment Securities) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/FairValueOfFinancialInstrumentsDetails" id="FairValueOfFinancialInstrumentsDetails">
        <link:definition>00570 - Disclosure - Fair Value of Financial Instruments (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/RevenueFromContractsWithCustomersScheduleOfRevenueFromContractsWithCustomersDetails" id="RevenueFromContractsWithCustomersScheduleOfRevenueFromContractsWithCustomersDetails">
        <link:definition>00580 - Disclosure - Revenue from Contracts with Customers (Schedule of Revenue from Contracts with Customers) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/LeasesNarrativeDetails" id="LeasesNarrativeDetails">
        <link:definition>00590 - Disclosure - Leases (Narrative) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://cassinfo.com/role/LeasesScheduleOfOperatingLeaseLiabilitiesDetails" id="LeasesScheduleOfOperatingLeaseLiabilitiesDetails">
        <link:definition>00600 - Disclosure - Leases (Schedule of operating lease liabilities) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
    </appinfo>
  </annotation>
  <import namespace="http://www.xbrl.org/2003/instance" schemaLocation="http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd"/>
  <import namespace="http://www.xbrl.org/2003/linkbase" schemaLocation="http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd"/>
  <import namespace="http://xbrl.org/2005/xbrldt" schemaLocation="http://www.xbrl.org/2005/xbrldt-2005.xsd"/>
  <import namespace="http://fasb.org/us-gaap/2020-01-31" schemaLocation="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd"/>
  <import namespace="http://xbrl.sec.gov/country/2020-01-31" schemaLocation="https://xbrl.sec.gov/country/2020/country-2020-01-31.xsd"/>
  <import namespace="http://xbrl.sec.gov/currency/2020-01-31" schemaLocation="https://xbrl.sec.gov/currency/2020/currency-2020-01-31.xsd"/>
  <import namespace="http://xbrl.sec.gov/exch/2020-01-31" schemaLocation="https://xbrl.sec.gov/exch/2020/exch-2020-01-31.xsd"/>
  <import namespace="http://xbrl.sec.gov/naics/2017-01-31" schemaLocation="http://xbrl.sec.gov/naics/2017/naics-2017-01-31.xsd"/>
  <import namespace="http://xbrl.sec.gov/sic/2020-01-31" schemaLocation="https://xbrl.sec.gov/sic/2020/sic-2020-01-31.xsd"/>
  <import namespace="http://xbrl.sec.gov/stpr/2018-01-31" schemaLocation="https://xbrl.sec.gov/stpr/2018/stpr-2018-01-31.xsd"/>
  <import namespace="http://www.xbrl.org/2009/role/negated" schemaLocation="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd"/>
  <import namespace="http://www.xbrl.org/2009/role/net" schemaLocation="http://www.xbrl.org/lrr/role/net-2009-12-16.xsd"/>
  <import namespace="http://xbrl.sec.gov/dei/2019-01-31" schemaLocation="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd"/>
  <import namespace="http://www.xbrl.org/dtr/type/numeric" schemaLocation="http://www.xbrl.org/dtr/type/numeric-2009-12-16.xsd"/>
  <import namespace="http://www.xbrl.org/dtr/type/non-numeric" schemaLocation="http://www.xbrl.org/dtr/type/nonNumeric-2009-12-16.xsd"/>
  <import namespace="http://fasb.org/us-types/2019-01-31" schemaLocation="http://xbrl.fasb.org/us-gaap/2020/elts/us-types-2020-01-31.xsd"/>
  <import namespace="http://fasb.org/srt/2020-01-31" schemaLocation="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd"/>
  <import namespace="http://fasb.org/srt-types/2020-01-31" schemaLocation="http://xbrl.fasb.org/srt/2020/elts/srt-types-2020-01-31.xsd"/>
  <element name="CreditExposureOfLoanPortfolioDomain" id="cass_CreditExposureOfLoanPortfolioDomain" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration"/>
  <element name="LoansSubjectToNormalMonitoringMember" id="cass_LoansSubjectToNormalMonitoringMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration"/>
  <element name="IncreaseDecreaseInAccountsAndDraftsPayable" id="cass_IncreaseDecreaseInAccountsAndDraftsPayable" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" xbrli:balance="credit"/>
  <element name="IndustrialRevenueBondMember" id="cass_IndustrialRevenueBondMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration"/>
  <element name="IntersegmentIncomeExpenseAfterProvisionForLoanLoss" id="cass_IntersegmentIncomeExpenseAfterProvisionForLoanLoss" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" xbrli:balance="credit"/>
  <element name="SharebasedCompensationArrangementsBySharebasedPaymentAwardOptionOutstandingWeightedAverageRemainingContractualTerm" id="cass_SharebasedCompensationArrangementsBySharebasedPaymentAwardOptionOutstandingWeightedAverageRemainingContractualTerm" type="xbrli:durationItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration"/>
  <element name="OtherFinancingReceivableMember" id="cass_OtherFinancingReceivableMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration"/>
  <element name="InvoicePaymentFeesInscopeFASBASC606" id="cass_InvoicePaymentFeesInscopeFASBASC606" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" xbrli:balance="credit"/>
  <element name="IncreaseDecreaseInInterestBearingDemandAndSavingsDeposits" id="cass_IncreaseDecreaseInInterestBearingDemandAndSavingsDeposits" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" xbrli:balance="debit"/>
  <element name="AssetsCarryingAmount" id="cass_AssetsCarryingAmount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="instant" xbrli:balance="debit"/>
  <element name="InterestOnFederalFundsSoldAndOtherShortTermInvestments" id="cass_InterestOnFederalFundsSoldAndOtherShortTermInvestments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" xbrli:balance="credit"/>
  <element name="RealEstateFaithbasedConstructionLoanMember" id="cass_RealEstateFaithbasedConstructionLoanMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration"/>
  <element name="DocumentAndEntityInformationAbstract" id="cass_DocumentAndEntityInformationAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration"/>
  <element name="AccountsAndDraftsPayableFairValueDisclosure" id="cass_AccountsAndDraftsPayableFairValueDisclosure" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="instant" xbrli:balance="credit"/>
  <element name="AccountsAndDraftsPayable" id="cass_AccountsAndDraftsPayable" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="instant" xbrli:balance="credit"/>
  <element name="RealEstateCommercialConstructionLoanMember" id="cass_RealEstateCommercialConstructionLoanMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration"/>
  <element name="CreditExposureOfLoanPortfolioAxis" id="cass_CreditExposureOfLoanPortfolioAxis" type="xbrli:stringItemType" substitutionGroup="xbrldt:dimensionItem" abstract="true" nillable="true" xbrli:periodType="duration"/>
  <element name="LiabilitiesCarryingValue" id="cass_LiabilitiesCarryingValue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="instant" xbrli:balance="credit"/>
  <element name="InvoiceProcessingFeesInscopeFASBASC606" id="cass_InvoiceProcessingFeesInscopeFASBASC606" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" xbrli:balance="credit"/>
  <element name="BankingServicesMember" id="cass_BankingServicesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration"/>
  <element name="NetInterestIncomeAfterProvisionForLoanLossesOutofscopeFASBASC606" id="cass_NetInterestIncomeAfterProvisionForLoanLossesOutofscopeFASBASC606" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" xbrli:balance="credit"/>
  <element name="OtherIncomeOutofscopeFASBASC606" id="cass_OtherIncomeOutofscopeFASBASC606" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" xbrli:balance="credit"/>
  <element name="CommercialAndIndustrialLoanMember" id="cass_CommercialAndIndustrialLoanMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration"/>
  <element name="DefinedBenefitPlanPensionPeriod" id="cass_DefinedBenefitPlanPensionPeriod" type="xbrli:durationItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration"/>
  <element name="FederalFundsSoldAndOtherShortTermInvestments" id="cass_FederalFundsSoldAndOtherShortTermInvestments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="instant" xbrli:balance="debit"/>
  <element name="ScheduleOfLoanCategoriesTableTextBlock" id="cass_ScheduleOfLoanCategoriesTableTextBlock" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration"/>
  <element name="StandbyLettersOfCreditOutstanding" id="cass_StandbyLettersOfCreditOutstanding" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="instant" xbrli:balance="credit"/>
  <element name="IncomeFromCustomersAfterProvisionForLoanLoss" id="cass_IncomeFromCustomersAfterProvisionForLoanLoss" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" xbrli:balance="credit"/>
  <element name="IntangibleAssetsAccumulatedAmortization" id="cass_IntangibleAssetsAccumulatedAmortization" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="instant" xbrli:balance="credit"/>
  <element name="PercentageOfTargetOpportunityForAwardsToVest" id="cass_PercentageOfTargetOpportunityForAwardsToVest" type="num:percentItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration"/>
  <element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerms" id="cass_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerms" type="xbrli:durationItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration"/>
  <element name="FeeRevenueInscopeFASBASC606" id="cass_FeeRevenueInscopeFASBASC606" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" xbrli:balance="credit"/>
  <element name="InformationServicesPaymentAndProcessingRevenue" id="cass_InformationServicesPaymentAndProcessingRevenue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" xbrli:balance="credit"/>
  <element name="BankServiceFees" id="cass_BankServiceFees" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" xbrli:balance="credit"/>
  <element name="IncreaseDecreaseInPaymentsInExcessOfFunding" id="cass_IncreaseDecreaseInPaymentsInExcessOfFunding" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" xbrli:balance="credit"/>
  <element name="PaymentsInExcessOfFunding" id="cass_PaymentsInExcessOfFunding" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="instant" xbrli:balance="debit"/>
  <element name="InformationServicesMember" id="cass_InformationServicesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration"/>
  <element name="OtherLoanMember" id="cass_OtherLoanMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration"/>
  <element name="IncreaseDecreaseInNonInterestBearingDemandDeposits" id="cass_IncreaseDecreaseInNonInterestBearingDemandDeposits" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" xbrli:balance="debit"/>
  <element name="March2020Member" id="cass_March2020Member" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration"/>
  <element name="AvailableForSaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosurePercentage" id="cass_AvailableForSaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosurePercentage" type="num:percentItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="instant"/>
  <element name="FundingSources" id="cass_FundingSources" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" xbrli:balance="credit"/>
  <element name="UnamortizedIntangibleAssetAbstract" id="cass_UnamortizedIntangibleAssetAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration"/>
  <element name="RealEstateFaithbasedMortgageMember" id="cass_RealEstateFaithbasedMortgageMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration"/>
  <element name="ScheduleOfCreditExposureOfLoanPortfolioByInternallyAssignedCreditGradeTableTextBlock" id="cass_ScheduleOfCreditExposureOfLoanPortfolioByInternallyAssignedCreditGradeTableTextBlock" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration"/>
  <element name="CorporateEliminationsAndOtherMember" id="cass_CorporateEliminationsAndOtherMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration"/>
  <element name="PerformanceBasedRestrictedSharesMember" id="cass_PerformanceBasedRestrictedSharesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration"/>
  <element name="AccountAndDraftsPayable" id="cass_AccountAndDraftsPayable" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="instant" xbrli:balance="credit"/>
  <element name="RealEstateCommercialMortgageMember" id="cass_RealEstateCommercialMortgageMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration"/>
  <element name="NonperformingLoansSubjectToSpecialMonitoringMember" id="cass_NonperformingLoansSubjectToSpecialMonitoringMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration"/>
  <element name="PerformingLoansSubjectToSpecialMonitoringMember" id="cass_PerformingLoansSubjectToSpecialMonitoringMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration"/>
</schema>
