<?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>0001203689</cik>
          <ccc>XXXXXXXX</ccc>
        </filerCredentials>
      </filer>
      <liveTestFlag>LIVE</liveTestFlag>



    </filerInfo>
  </headerData>
  <formData>
    <issuerInfo>
      <issuerCik>0000814547</issuerCik>
      <issuerName>FAIR ISAAC CORP</issuerName>
      <secFileNumber>001-11689</secFileNumber>
      <issuerAddress>
        <com:street1>5 WEST MENDENHALL</com:street1>
        <com:street2>SUITE 105</com:street2>
        <com:city>BOZEMAN</com:city>
        <com:stateOrCountry>MT</com:stateOrCountry>
        <com:zipCode>59715</com:zipCode>
      </issuerAddress>
      <issuerContactPhone>(406) 982-7276</issuerContactPhone>
      <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>KIRSNER JAMES</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
      <relationshipsToIssuer>
        <relationshipToIssuer>Director</relationshipToIssuer>
      </relationshipsToIssuer>
    </issuerInfo>
    <securitiesInformation>
      <securitiesClassTitle>Common</securitiesClassTitle>
      <brokerOrMarketmakerDetails>
        <name>Charles Schwab Corp</name>
        <address>
          <com:street1>3000 Schwab Way</com:street1>
          <com:city>Westlake</com:city>
          <com:stateOrCountry>TX</com:stateOrCountry>
          <com:zipCode>76262</com:zipCode>
        </address>
      </brokerOrMarketmakerDetails>
      <noOfUnitsSold>4000</noOfUnitsSold>
      <aggregateMarketValue>6783600.00</aggregateMarketValue>
      <noOfUnitsOutstanding>24518533</noOfUnitsOutstanding>
      <approxSaleDate>08/07/2024</approxSaleDate>
      <securitiesExchangeName>NYSE</securitiesExchangeName>
    </securitiesInformation>
    <securitiesToBeSold>
      <securitiesClassTitle>Common</securitiesClassTitle>
      <acquiredDate>02/24/2024</acquiredDate>
      <natureOfAcquisitionTransaction>Exercised Options</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>369</amountOfSecuritiesAcquired>
      <paymentDate>02/24/2024</paymentDate>
      <natureOfPayment>Cash</natureOfPayment>
    </securitiesToBeSold>
    <securitiesToBeSold>
      <securitiesClassTitle>Common</securitiesClassTitle>
      <acquiredDate>03/03/2023</acquiredDate>
      <natureOfAcquisitionTransaction>Exercised Options</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>537</amountOfSecuritiesAcquired>
      <paymentDate>03/03/2023</paymentDate>
      <natureOfPayment>Cash</natureOfPayment>
    </securitiesToBeSold>
    <securitiesToBeSold>
      <securitiesClassTitle>Common</securitiesClassTitle>
      <acquiredDate>02/24/2016</acquiredDate>
      <natureOfAcquisitionTransaction>Exercised Options</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>1039</amountOfSecuritiesAcquired>
      <paymentDate>02/24/2016</paymentDate>
      <natureOfPayment>Cash</natureOfPayment>
    </securitiesToBeSold>
    <securitiesToBeSold>
      <securitiesClassTitle>Common</securitiesClassTitle>
      <acquiredDate>02/25/2015</acquiredDate>
      <natureOfAcquisitionTransaction>Exercised Options</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>2055</amountOfSecuritiesAcquired>
      <paymentDate>02/25/2015</paymentDate>
      <natureOfPayment>Cash</natureOfPayment>
    </securitiesToBeSold>
    <nothingToReportFlagOnSecuritiesSoldInPast3Months>Y</nothingToReportFlagOnSecuritiesSoldInPast3Months>
    <remarks>Account Title: Kirsner Family Trust U/A DTD 5/24/93 - James D. Kirsner and Joan C. Kirsner as trustees</remarks>
    <noticeSignature>
      <noticeDate>08/07/2024</noticeDate>
      <signature>James Kirsner</signature>
    </noticeSignature>
  </formData>
</edgarSubmission>
[{"type": "144", "sequence": "1", "filename": "primary_doc.xml", "secsgml_size_bytes": 4417}]
144
0001203689
XXXXXXXX
LIVE
0000814547
FAIR ISAAC CORP
001-11689
5 WEST MENDENHALL
SUITE 105
BOZEMAN
MT
59715
(406) 982-7276
KIRSNER JAMES
Director
Common
Charles Schwab Corp
3000 Schwab Way
Westlake
TX
76262
4000
6783600.00
24518533
08/07/2024
NYSE
Common
02/24/2024
Exercised Options
Issuer
N
369
02/24/2024
Cash
Common
03/03/2023
Exercised Options
Issuer
N
537
03/03/2023
Cash
Common
02/24/2016
Exercised Options
Issuer
N
1039
02/24/2016
Cash
Common
02/25/2015
Exercised Options
Issuer
N
2055
02/25/2015
Cash
Y
Account Title: Kirsner Family Trust U/A DTD 5/24/93 - James D. Kirsner and Joan C. Kirsner as trustees
08/07/2024
James Kirsner