EXHIBIT 5.01


                                 June 11, 2002


HNC Software Inc.
5935 Cornerstone Court West
San Diego, CA 92121-3728

Gentlemen/Ladies:

        At your request, we have examined the Registration Statement on Form S-8
to be filed by HNC Software Inc., a Delaware corporation (the "COMPANY"), with
the Securities and Exchange Commission (the "COMMISSION") on or about June 11,
2002 (the "REGISTRATION STATEMENT"), in connection with the registration under
the Securities Act of 1933, as amended, of an aggregate of 354,255 shares of the
Company's Common Stock, $0.001 par value (the "SHARES"), that are subject to
issuance by the Company upon the exercise of stock purchase rights to be granted
by the Company's under its 1995 Employee Stock Purchase Plan, as amended (the
"PURCHASE PLAN").

        In rendering this opinion, we have examined the following:

        (1)  the Company's Restated Certificate of Incorporation, as amended by
             the Certificate of Amendment filed with the Delaware Secretary of
             State on June 12, 2000, both certified by the Delaware Secretary of
             State on June 4, 2002.

        (2)  the Company's Bylaws, as amended, certified by the Company's
             Secretary on May 30, 2002.

        (3)  the Registration Statement, together with the Exhibits filed as a
             part thereof or incorporated therein by reference;

        (4)  the prospectus prepared in connection with the Registration
             Statement;

        (5)  the minutes of meetings and actions by written consent of the
             stockholders and Board of Directors that are contained in the
             Company's minute books that are in our possession;

        (6)  a certificate from the Company's transfer agent dated January 2,
             2002, certifying the number of the Company's issued and outstanding
             shares of capital stock as of December 31, 2001;

        (7)  a certificate from the Company's transfer agent dated April 30,
             2002 certifying the number of the Company's issued and outstanding
             shares of capital stock as of April 30, 2002;

        (8)  a statement from the Company as to the number of outstanding
             options, warrants and rights to purchase the Company's capital
             stock and any additional shares of the Company's Common Stock
             reserved for future issuance in connection with the Company's stock
             option and purchase plans and all other plans, agreements or rights
             as of April 30, 2002; and

        (9)  a Management Certificate addressed to us and dated of even date
             herewith executed by the Company and containing certain factual and
             other representations (the "MANAGEMENT CERTIFICATE").

        In our examination of documents for purposes of this opinion, we have
assumed, and express no opinion as to, the genuineness of all signatures on
original documents, the authenticity and completeness of all documents submitted
to us as originals, the conformity to originals and completeness of all
documents submitted to us as copies, the legal capacity of all persons or
entities executing the same, the lack of any undisclosed termination,
modification,



waiver or amendment to any document reviewed by us and the due authorization,
execution and delivery of all documents where due authorization, execution and
delivery are prerequisites to the effectiveness thereof.

        As to matters of fact relevant to this opinion, we have relied solely
upon our examination of the documents referred to above and have assumed the
current accuracy and completeness of the information obtained from the documents
referred to above and the representations and warranties made by representatives
of the Company to us, including but not limited to those set forth in the
Management Certificate. We have made no independent investigation or other
attempt to verify the accuracy of any of such information or to determine the
existence or non-existence of any other factual matters; however, we are not
aware of any facts that would cause us to believe that the opinion expressed
herein is not accurate.

        We are admitted to practice law in the State of California, and we
render this opinion only with respect to, and express no opinion herein
concerning the application or effect of the laws of any jurisdiction other than,
the existing laws of the United States of America and, with respect to the
validity of corporate action and the requirements for the issuance of stock, of
the Delaware General Corporation Law, the Delaware Constitution and reported
judicial decisions relating thereto.

        Based upon the foregoing, it is our opinion that the 354,255 Shares
that may be issued and sold by the Company upon the exercise of purchase rights
to be granted under the Purchase Plan, when issued, sold and delivered in
accordance with the Purchase Plan and the purchase agreements to be entered into
thereunder and in the manner and for the consideration stated in the
Registration Statement and the relevant prospectus, will be validly issued,
fully paid and nonassessable.

        We consent to the use of this opinion as an exhibit to the Registration
Statement and further consent to all references to us, if any, in the
Registration Statement, the prospectus constituting a part thereof and any
amendments thereto. This opinion is intended solely for use in connection with
the issuance and sale of shares subject to the Registration Statement and is not
to be relied upon for any other purpose. We assume no obligation to advise you
of any fact, circumstance, event or change in the law or the facts that may
hereafter be brought to our attention whether or not such occurrence would
affect or modify the opinions expressed herein.

                                                 Very truly yours,

                                                 /s/ Fenwick & West LLP


                                                 FENWICK & WEST LLP


                                       2