Exhibit 10.1


                      SECOND AMENDMENT TO CREDIT AGREEMENT


      THIS SECOND AMENDMENT TO CREDIT AGREEMENT (this "Amendment") is entered
into as of February 1, 2004, by and between FAIR ISAAC CORPORATION (FORMERLY
KNOWN AS FAIR, ISAAC AND COMPANY, INCORPORATED), a Delaware corporation
("Borrower"), and WELLS FARGO BANK, NATIONAL ASSOCIATION ("Bank").


                                    RECITALS

      WHEREAS, Borrower is currently indebted to Bank pursuant to the terms and
conditions of that certain Credit Agreement between Borrower and Bank dated as
of November 1, 2002, as amended from time to time ("Credit Agreement").

      WHEREAS, Bank and Borrower have agreed to certain changes in the terms and
conditions set forth in the Credit Agreement and have agreed to amend the Credit
Agreement to reflect said changes.

      NOW, THEREFORE, for valuable consideration, the receipt and sufficiency of
which are hereby acknowledged, the parties hereto agree that the Credit
Agreement shall be amended as follows:

      1.    Section 1.1.(a) is hereby amended by deleting "February 1, 2004" as
the last day on which Bank will make advances under the Line of Credit, and by
substituting for said date "February 1, 2006," with such change to be effective
upon the execution and delivery to Bank of a promissory note dated February 1,
2004 (which promissory note shall replace and be deemed the Line of Credit Note
defined in and made pursuant to the Credit Agreement) and all other contracts,
instruments and documents required by Bank to evidence such change.

      2.    Section 1.2.(a) is hereby deleted in its entirety, and the following
substituted therefor:

                  "(a)  Foreign Exchange Facility. Subject to the terms and
            conditions of this Agreement, Bank hereby agrees to make available
            to Borrower a facility (the "Foreign Exchange Facility") under which
            Bank, from time to time up to and including February 1, 2006, will
            enter into foreign exchange contracts for the account of Borrower
            for the purchase and/or sale by Borrower in United States dollars of
            Euro, Pound, Japanese yen, Australian dollars, Rand, Canadian
            dollars, Mexican Peso, Singapore dollars and Brazilian real;
            provided however, that the maximum amount of all outstanding foreign
            exchange contracts shall not at any time exceed an aggregate of
            Twenty-five Million United States Dollars (US$25,000,000.00). No
            foreign exchange contract shall be executed for a term which extends
            beyond February 1, 2006. Borrower shall have a "Delivery Limit"
            under the Foreign Exchange Facility not to exceed at any time the
            aggregate principal amount of Five Million United States Dollars
            (US$5,000,000.00), which Delivery Limit reflects the maximum
            principal amount of Borrower's foreign exchange contracts which


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            may mature during any two (2) day period. All foreign exchange
            transactions shall be subject to the additional terms of a Foreign
            Exchange Agreement, substantially in the form of EXHIBIT B attached
            hereto ("Foreign Exchange Agreement"), all terms of which are
            incorporated herein by this reference."

      3.    In consideration of the changes set forth herein and as a condition
to the effectiveness hereof, immediately upon signing this Amendment Borrower
shall pay to Bank a non-refundable fee of $7,500.00 per annum.

      4.    Except as specifically provided herein, all terms and conditions of
the Credit Agreement remain in full force and effect, without waiver or
modification. All terms defined in the Credit Agreement shall have the same
meaning when used in this Amendment. This Amendment and the Credit Agreement
shall be read together, as one document.

      5.    Borrower hereby remakes all representations and warranties contained
in the Credit Agreement and reaffirms all covenants set forth therein. Borrower
further certifies that as of the date of this Amendment there exists no Event of
Default as defined in the Credit Agreement, nor any condition, act or event
which with the giving of notice or the passage of time or both would constitute
any such Event of Default.

      IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be
executed as of the day and year first written above.

                                          WELLS FARGO BANK,
FAIR ISAAC CORPORATION                      NATIONAL ASSOCIATION


By:  /s/ KENNETH J. SAUNDERS             By: /s/ LAURA KAY MATHERLY
     -----------------------                 ----------------------
                                             Laura Kay Matherly
Title:  CHIEF FINANCIAL OFFICER           Vice President
       ---------------------------


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