content: <?xml version="1.0" encoding="UTF-8"?><edgarSubmission xmlns="http://www.sec.gov/edgar/ownership" xmlns:com="http://www.sec.gov/edgar/common">
    <headerData>
      <submissionType>144</submissionType>
      <filerInfo>
        <filer>
          <filerCredentials>
            <cik>0001382512</cik>
            <ccc>XXXXXXXX</ccc>
          </filerCredentials>
        </filer>
        <liveTestFlag>LIVE</liveTestFlag>
  
  
  
      </filerInfo>
    </headerData>
    <formData>
      <issuerInfo>
        <issuerCik>0001005757</issuerCik>
        <issuerName>CSG SYSTEMS INTERNATIONAL INC</issuerName>
        <secFileNumber>000-27512</secFileNumber>
        <issuerAddress>
          <com:street1>169 INVERNESS DR W</com:street1>
          <com:street2>SUITE 300</com:street2>
          <com:city>ENGLEWOOD</com:city>
          <com:stateOrCountry>CO</com:stateOrCountry>
          <com:zipCode>80112</com:zipCode>
        </issuerAddress>
        <issuerContactPhone>3037962850</issuerContactPhone>
        <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>Cooper Ronald</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
        <relationshipsToIssuer>
          <relationshipToIssuer>Director</relationshipToIssuer>
        </relationshipsToIssuer>
      </issuerInfo>
      <securitiesInformation>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <brokerOrMarketmakerDetails>
          <name>Fidelity Brokerage Services LLC</name>
          <address>
            <com:street1>900 Salem Street</com:street1>
            <com:city>Smithfield</com:city>
            <com:stateOrCountry>RI</com:stateOrCountry>
            <com:zipCode>02917</com:zipCode>
          </address>
        </brokerOrMarketmakerDetails>
        <noOfUnitsSold>9000</noOfUnitsSold>
        <aggregateMarketValue>599183.09</aggregateMarketValue>
        <noOfUnitsOutstanding>28839469</noOfUnitsOutstanding>
        <approxSaleDate>02/25/2025</approxSaleDate>
        <securitiesExchangeName>NASDAQ</securitiesExchangeName>
      </securitiesInformation>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>09/10/2019</acquiredDate>
        <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>3000</amountOfSecuritiesAcquired>
        <paymentDate>09/10/2019</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>05/17/2022</acquiredDate>
        <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>3672</amountOfSecuritiesAcquired>
        <paymentDate>05/17/2022</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>05/16/2023</acquiredDate>
        <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>2328</amountOfSecuritiesAcquired>
        <paymentDate>05/16/2023</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <nothingToReportFlagOnSecuritiesSoldInPast3Months>Y</nothingToReportFlagOnSecuritiesSoldInPast3Months>
      <noticeSignature>
        <noticeDate>02/25/2025</noticeDate>
        <signature>/s/ Eric Janiak, as a duly authorized representative of Fidelity Brokerage Services LLC, as attorney-in-fact for Ronald H. Cooper</signature>
      </noticeSignature>
    </formData>
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text: 144
  0001382512
  XXXXXXXX
  LIVE
  0001005757
  CSG SYSTEMS INTERNATIONAL INC
  000-27512
  169 INVERNESS DR W
  SUITE 300
  ENGLEWOOD
  CO
  80112
  3037962850
  Cooper Ronald
  Director
  Common
  Fidelity Brokerage Services LLC
  900 Salem Street
  Smithfield
  RI
  02917
  9000
  599183.09
  28839469
  02/25/2025
  NASDAQ
  Common
  09/10/2019
  Restricted Stock Vesting
  Issuer
  N
  3000
  09/10/2019
  Compensation
  Common
  05/17/2022
  Restricted Stock Vesting
  Issuer
  N
  3672
  05/17/2022
  Compensation
  Common
  05/16/2023
  Restricted Stock Vesting
  Issuer
  N
  2328
  05/16/2023
  Compensation
  Y
  02/25/2025
  /s/ Eric Janiak, as a duly authorized representative of Fidelity Brokerage Services LLC, as attorney-in-fact for Ronald H. Cooper