<PAGE>


                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                   FORM 10-K/A
                                (Amendment No. 1)

                                   (Mark One)

[X]  ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE
     ACT OF 1934

     For the fiscal year ended December 31, 2001

                                       OR

[ ]  TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES
     EXCHANGE ACT OF 1934

     For the transition period from            to

                         Commission file number 0-27501

                            The TriZetto Group, Inc.
             (Exact name of registrant as specified in its charter)

           Delaware                                        33-0761159
 (State or other jurisdiction of                        (I.R.S. Employer
  incorporation or organization)                        Identification No.)

                        567 San Nicolas Drive, Suite 360
                         Newport Beach, California 92660
              (Address of principal executive offices and Zip Code)

Registrant's telephone number, including area code: (949) 719-2200

Securities registered pursuant to section 12(b) of the Act: None

Securities registered pursuant to Section 12(g) of the Act: Common Stock, $0.001
par value, and Series A Junior Participating Preferred Stock, $0.001 par value

                                ----------------

Indicate by check mark whether the registrant (1) has filed all reports required
to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during
the preceding 12 months (or for such shorter period that the registrant was
required to file such reports), and (2) has been subject to such filing
requirements for the past 90 days.

                               Yes  [X]    No   [_]
                                  -------     --------

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405
of Regulation S-K is not contained herein, and will not be contained, to the
best of registrant's knowledge, in definitive proxy or information statements
incorporated by reference in Part III of this Form 10-K or any amendment to this
Form 10-K. [X]

The aggregate market value of common stock held by non-affiliates as of May 28,
2002 (based upon the closing price of such shares on the Nasdaq National Market
System) was approximately $300.8 million. Such calculation excludes the shares
of common stock beneficially owned at such date by the directors and executive
officers of the registrant and by IMS Health Incorporated. In making such
calculation, registrant does not determine the affiliate or non-affiliate status
of any holders of the shares of common stock for any other purpose.

As of May 28, 2002, 45,439,486 shares of common stock were outstanding.

                       Documents Incorporated by Reference

Portions of Registrant's Proxy Statement relating to its 2002 Annual Meeting of
Stockholders are incorporated by reference into Part III of this report.

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                                EXPLANATORY NOTE

     We are filing this Amendment No. 1 on Form 10-K/A to file a consent of
Ernst & Young LLP to the incorporation by reference in our Registration
Statements on Forms S-3 (Nos. 333-52490 and 333-47764) and S-8 (Nos. 333-52488,
333-43220, 333-94817 and 333-92729) of the report of Ernst & Young LLP dated
February 1, 2002 with respect to our consolidated financial statements and
schedule included in our Form 10-K for the year ended December 31, 2001. The
consent is filed herewith as Exhibit 23.2.

                                     PART IV

Item 14 -- Exhibits, Financial Statement Schedules and Reports On Form 8-K.

(a) List of documents filed as part of this Form 10-K/A:

    (1) Financial Statements.

        See Index to Financial Statements and Schedule on page F-1.

    (2) Financial Statement Schedules.

        See Index to Financial Statements and Schedule on page F-1.

    (3) Exhibits.

        The following exhibits are filed (or incorporated by reference herein)
        as part of this Form 10-K/A:

    Exhibit
     Number                        Description of Exhibit
    -------                        ----------------------

     2.1*        Agreement and Plan of Reorganization, dated as of May 16, 2000,
                 by and among TriZetto, Elbejay Acquisition Corp., IMS Health
                 Incorporated and Erisco Managed Care Technologies, Inc.
                 (Incorporated by reference to Exhibit 2.1 of TriZetto's Form
                 8-K as filed with the SEC on May 19, 2000, File No. 000-27501)

     2.2*        Agreement and Plan of Merger, dated as of November 2, 2000, by
                 and among TriZetto, Cidadaw Acquisition Corp., Resource
                 Information Management Systems, Inc. ("RIMS"), the shareholders
                 of RIMS, Terry L. Kirch and Thomas H. Heimsoth (Incorporated by
                 reference to Exhibit 2.1 of TriZetto's Form 8-K as filed with
                 the SEC on December 18, 2000, File No. 000-27501)

     2.3*        First Amendment to Agreement and Plan of Merger, dated as of
                 December 1, 2000, by and among TriZetto, Cidadaw Acquisition
                 Corp., RIMS, the shareholders of RIMS, Terry L. Kirch and
                 Thomas H. Heimsoth (Incorporated by reference to Exhibit 2.2 of
                 TriZetto's Form 8-K as filed with the SEC on December 18, 2000,
                 File No. 000-27501)

     3.1*        Form of Amended and Restated Certificate of Incorporation of
                 TriZetto, as filed with the Delaware Secretary of State
                 effective as of October 14, 1999 (Incorporated by reference to
                 Exhibit 3.2 of TriZetto's Registration Statement on Form S-1/A,
                 as filed with the SEC on September 14, 1999, File No.
                 333-84533)

     3.2*        Certificate of Amendment of Amended and Restated Certificate of
                 Incorporation of TriZetto, dated October 3, 2000 (Incorporated
                 by reference to Exhibit 3.1 of TriZetto's Form 10-Q as filed
                 with the SEC on November 14, 2000, File No. 000-27501)

     3.3*        Certificate of Designation of Rights, Preferences and
                 Privileges of Series A Junior Participating Preferred Stock of
                 TriZetto, dated October 17, 2000 (Incorporated by reference to
                 Exhibit 3.2 of TriZetto's Form 10-Q as filed with the SEC on
                 November 14, 2000, File No. 000-27501)

     3.4*        Amended and Restated Bylaws of TriZetto effective as of October
                 7, 1999 (Incorporated by reference to Exhibit 3.4 of TriZetto's
                 Registration Statement on Form S-1/A, as filed with the SEC on
                 August 18, 1999, File No. 333-84533)

     4.1*        Specimen common stock certificate (Incorporated by reference to
                 Exhibit 4.1 of TriZetto's Registration Statement on Form S-1/A
                 as filed with the SEC on September 14, 1999, File No.
                 333-84533)

     4.2*        Rights Agreement, dated October 2, 2000, by and between
                 TriZetto and U.S. Stock Transfer Corporation (Incorporated by
                 reference to Exhibit 2.1 of TriZetto's Form 8-A12G as filed
                 with the SEC on October 19, 2000, File No. 000-27501)

    10.1*        First Amended and Restated 1998 Stock Option Plan (Incorporated
                 by reference to Exhibit 4.1 of TriZetto's Form S-8 as filed
                 with the SEC on August 7, 2000, File No. 333-43220)

                                       2

<PAGE>

    Exhibit
     Number                        Description of Exhibit
    -------                        ----------------------

    10.2*        Form of 1998 Incentive Stock Option Agreement (Incorporated by
                 reference to Exhibit 10.2 of TriZetto's Registration Statement
                 on Form S-1 as filed with the SEC on August 5, 1999, File No.
                 333-84533)

    10.3*        Form of 1998 Non-Qualified Stock Option Agreement (Incorporated
                 by reference to Exhibit 10.3 of TriZetto's Registration
                 Statement on Form S-1 as filed with the SEC on August 5, 1999,
                 File No.
                 333-84533)

    10.4*        1999 Employee Stock Purchase Plan (Incorporated by reference to
                 Exhibit 10.4 of TriZetto's Registration Statement on Form S-1/A
                 as filed with the SEC on August 18, 1999, File No. 333-84533)

    10.5*        RIMS Stock Option Plan (Incorporated by reference to Exhibit
                 4.1 of TriZetto's Form S-8 as filed with the SEC on December
                 21, 2000, File No. 000-27501)

    10.6*        Employment Agreement, dated April 30, 1998, by and between
                 TriZetto and Jeffrey H. Margolis (Incorporated by reference to
                 Exhibit 10.5 of TriZetto's Registration Statement on Form S-1
                 as filed with the SEC on August 5, 1999, File No. 333-84533)

    10.7*        Promissory Note, dated April 30, 1998, by and between TriZetto
                 and Jeffrey H. Margolis (Incorporated by reference to Exhibit
                 10.6 of TriZetto's Registration Statement on Form S-1 as filed
                 with the SEC on August 5, 1999, File No. 333-84533)

    10.8*        Form of Indemnification Agreement (Incorporated by reference to
                 Exhibit 10.7 of TriZetto's Registration Statement on Form S-1
                 as filed with the SEC on August 5, 1999, File No. 333-84533)

    10.9*        Form of Restricted Stock Agreement between TriZetto and certain
                 consultants and employees (Incorporated by reference to Exhibit
                 10.3 of TriZetto's Form 10-Q as filed with the SEC on August
                 14, 2000, File No. 000-27501)

    10.10*       Form of Change of Control Agreement entered into by and between
                 TriZetto and certain executive officers of TriZetto effective
                 as of February 18, 2000 (Incorporated by reference to Exhibit
                 10.1 of TriZetto's Form 10-Q as filed with the SEC on May 15,
                 2000, File No. 000-27501)

    10.11*       First Amended and Restated Investor Rights Agreement, dated
                 April 9, 1999 by and among Raymond Croghan, Jeffrey Margolis,
                 TriZetto, and Series A and Series B Preferred Stockholders
                 (Incorporated by reference to Exhibit 10.8 of TriZetto's
                 Registration Statement on Form S-1/A, as filed with the SEC on
                 August 18, 1999, File No. 333-84533)

    10.12*       Office Lease Agreement, dated April 26, 1999, between St. Paul
                 Properties, Inc. and TriZetto (including addendum)
                 (Incorporated by reference to Exhibit 10.10 of TriZetto's
                 Registration Statement on Form S-1 as filed with the SEC on
                 August 5, 1999, File No. 333-84533)

    10.13*       Sublease Agreement, dated December 18, 1998, between TPI
                 Petroleum, Inc. and TriZetto (including underlying Office Lease
                 Agreement by and between St. Paul Properties, Inc. and Total,
                 Inc.) (Incorporated by reference to Exhibit 10.11 of TriZetto's
                 Registration Statement on Form S-1 as filed with the SEC on
                 August 5, 1999, File No. 333-84533)

    10.14*       First Modification and Ratification of Lease, dated November 1,
                 1999, by and between TriZetto and St. Paul Properties, Inc.
                 (Incorporated by reference to Exhibit 10.22 of TriZetto's Form
                 10-K as filed with the SEC on March 30, 2000, File No.
                 000-27501)

    10.15*       Second Modification and Ratification of Lease, dated December
                 1999, by and between TriZetto and St. Paul Properties, Inc.
                 (Incorporated by reference to Exhibit 10.23 of TriZetto's Form
                 10-K as filed with the SEC on March 30, 2000, File No.
                 000-27501)

    10.16*       Third Modification and Ratification of Lease, dated January 15,
                 2000, by and between TriZetto and St. Paul Properties, Inc.
                 (Incorporated by reference to Exhibit 10.16 of TriZetto's Form
                 10-K as filed with the SEC on April 2, 2001, File No.
                 000-27501)

    10.17*       Fourth Modification and Ratification of Lease, dated October
                 15, 2000, by and between TriZetto and St. Paul Properties, Inc.
                 (Incorporated by reference to Exhibit 10.17 TriZetto's Form
                 10-K as filed with the SEC on April 2, 2001, File No.
                 000-27501)

    10.18*       Form of Voting Agreement (Incorporated by reference to Exhibit
                 2.1 of TriZetto's Form 8-K as filed with the SEC on May 19,
                 2000, File No. 000-27501)

    10.19*       Secured Term Note, dated September 11, 2000, payable by
                 TriZetto and each of TriZetto's subsidiaries to Heller
                 Healthcare Finance, Inc. (Incorporated by reference to Exhibit
                 10.1 of TriZetto's Form 10-Q as filed with the SEC on November
                 14, 2000, File No. 000-27501)

    10.20*       Loan and Security Agreement, dated September 11, 2000, by and
                 among TriZetto, each of TriZetto's subsidiaries, and Heller
                 Healthcare Finance, Inc. (Incorporated by reference to Exhibit
                 10.2 of TriZetto's Form 10-Q as filed with the SEC on November
                 14, 2000, File No. 000-27501)

                                       3

<PAGE>

    Exhibit
     Number                        Description of Exhibit
    -------                        ----------------------

    10.21*       Revolving Credit Note, dated September 11, 2000, payable by
                 TriZetto and each of TriZetto's subsidiaries to Heller
                 Healthcare Finance, Inc. (Incorporated by reference to Exhibit
                 10.3 of TriZetto's Form 10-Q as filed with the SEC on November
                 14, 2000, File No. 000-27501)

    10.22*       Amendment No. 1 to Loan and Security Agreement, dated October
                 17, 2000, by and among TriZetto, each of TriZetto's
                 subsidiaries, and Heller Healthcare Finance, Inc. (Incorporated
                 by reference to Exhibit 10.4 of TriZetto's Form 10-Q as filed
                 with the SEC on November 14, 2000, File No.
                 000-27501)

    10.23*       Amended and Restated Revolving Credit Note, dated October 17,
                 2000, payable by TriZetto and each of TriZetto's subsidiaries
                 to Heller Healthcare Finance, Inc. (Incorporated by reference
                 to Exhibit 10.5 of TriZetto's Form 10-Q as filed with the SEC
                 on November 14, 2000, File No.
                 000-27501)

    10.24*       Amendment No. 2 to Loan and Security Agreement, dated December
                 28, 2000, by and among TriZetto, each of TriZetto's
                 subsidiaries, and Heller Healthcare Finance, Inc. (Incorporated
                 by reference to Exhibit 10.24 of TriZetto's Form 10-K as filed
                 with the SEC on April 2, 2001, File No.000-27501)

    10.25*       Second Amended and Restated Revolving Credit Note, dated
                 December 28, 2000, payable by TriZetto and each of TriZetto's
                 subsidiaries to Heller Healthcare Finance, Inc. (Incorporated
                 by reference to Exhibit 10.25 of TriZetto's Form 10-K as filed
                 with the SEC on April 2, 2001, File No.000-27501)

    10.26*       Bank One Credit Facility (including Promissory Note, Business
                 Loan Agreement and Commercial Pledge and Security Agreement),
                 dated October 27, 1999 (Incorporated by reference to Exhibit
                 10.21 of TriZetto's Form 10-K as filed with the SEC on March
                 30, 2000 File No. 000-27501)

    10.27*       Amendment to Bank One Credit Facility, dated June 22, 2000
                 (including Promissory Note Modification Agreement, Business
                 Loan Agreement and Commercial Pledge and Security Agreement)
                 (Incorporated by reference to Exhibit 10.27 of TriZetto's Form
                 10-K as filed with the SEC on April 2, 2001, File No.000-27501)

    10.28*       Amendment to Bank One Credit Facility, dated November 4, 2000
                 (including Change in Terms Agreement) (Incorporated by
                 reference to Exhibit 10.28 of TriZetto's Form 10-K as filed
                 with the SEC on April 2, 2001, File No.000-27501)

    10.29*       Stockholder Agreement, dated as of October 2, 2000, by and
                 between TriZetto and IMS Health Incorporated (Incorporated by
                 reference to Exhibit 10.29 of TriZetto's Form 10-K as filed
                 with the SEC on April 2, 2001, File No.000-27501)

    10.30*       Registration Rights Agreement, dated as of October 2, 2000, by
                 and between TriZetto and IMS Health Incorporated (Incorporated
                 by reference to Exhibit 10.30 of TriZetto's Form 10-K as filed
                 with the SEC on April 2, 2001, File No.000-27501)

    10.31*       Amendment to Bank One Credit Facility, dated March 29, 2001
                 (including Business Loan Agreement) (Incorporated by reference
                 to Exhibit 10.1 of TriZetto's Form 10-Q as filed with the SEC
                 on May 15, 2001, File No.000-27501)

    10.32*       Second Amended and Restated Stock Option Plan (Incorporated by
                 reference to Exhibit 4.1 of TriZetto's Form S-8 as filed with
                 the SEC on June 26, 2001, File No. 333-63902) (Incorporated by
                 reference to Exhibit 10.1 of TriZetto's Form 10-Q as filed with
                 the SEC on August 14, 2001, File No.000-27501)

    10.33*       Secured Term Note (Incorporated by reference to Exhibit 10.1 of
                 TriZetto's Form 10-Q as filed with the SEC on November 14,
                 2001, File No.000-27501)

    10.34*       Third Amended and Restated Revolving Credit Note (Incorporated
                 by reference to Exhibit 10.2 of TriZetto's Form 10-Q as filed
                 with the SEC on November 14, 2001, File No.000-27501)

    10.35*       Amendment No. 3 to Loan and Security Agreement (Incorporated by
                 reference to Exhibit 10.3 of TriZetto's Form 10-Q as filed with
                 the SEC on November 14, 2001, File No.000-27501)

    16.1*        Letter regarding Change in Certifying Accountants (Incorporated
                 by reference to Exhibit 16.1 of TriZetto's Form 10-Q as filed
                 with the SEC on August 14, 2001, File No.000-27501)

    21.1*        Current Subsidiaries of TriZetto

    23.1*        Consent of PricewaterhouseCoopers LLP

    23.2         Consent of Ernst & Young LLP

    24.1         Power of Attorney (included on the signature page to this Form
                 10-K/A)

*    Previously filed.


                                        4

<PAGE>


(b) Reports On Form 8-K.

     None.

                                   SIGNATURES

     Pursuant to the requirements of Section 13 or 15(d) of the Securities
Exchange Act of 1934, as amended, the registrant has duly caused this report to
be signed on its behalf by the undersigned thereunto duly authorized on June 25,
2002.

                                    THE TRIZETTO GROUP, INC.

                                    By:       /s/ JEFFREY H. MARGOLIS
                                       -----------------------------------------
                                                  Jeffrey H. Margolis,
                                             President, Chief Executive Officer
                                                  and Chairman of the Board

                                POWER OF ATTORNEY

     Each of the undersigned hereby constitutes and appoints Jeffrey H. Margolis
and Michael J. Sunderland, or either of them, his/her true and lawful
attorney-in-fact and agent, with full power of substitution and re-substitution,
to sign any or all amendments to the Form 10-K of The TriZetto Group, Inc. for
the year ended December 31, 2001 and to file the same, with all exhibits
thereto, and other documents in connection therewith, with the Securities and
Exchange Commission, hereby ratifying and confirming all that said
attorney-in-fact, or his/her substitute or substitutes, may do or cause to be
done by virtue hereof in any and all capacities.

     Pursuant to the requirements of the Securities Exchange Act of 1934, this
report has been signed below by the following persons on behalf of the
registrant and in the capacities and on the date indicated.

<TABLE>
<CAPTION>


                  Signature                                         Title                               Date
                  ---------                                         -----                               ----
         <S>                                   <C>                                                <C>

         /s/ JEFFREY H. MARGOLIS               President, Chief Executive Officer and              June 25, 2002
-----------------------------------------      Chairman of the Board (Principal Executive
            Jeffrey H. Margolis                Officer)


        /s/ MICHAEL J. SUNDERLAND              Senior Vice President of Finance, Chief             June 25, 2002
-----------------------------------------      Financial Officer and Secretary (Principal
           Michael J. Sunderland               Financial and Accounting Officer)


                                               Director                                            June 25, 2002
-----------------------------------------
             Sharon D. Garrett

      /s/    Willard A. Johnson, Jr.           Director                                            June 25, 2002
-----------------------------------------
          Willard A. Johnson, Jr.

         /s/    Donald J. Lothrop              Director                                            June 25, 2002
-----------------------------------------
             Donald J. Lothrop

                                               Director                                            June 25, 2002
-----------------------------------------
              Paul F. LeFort

            /s/    Eric D. Sipf                Director                                            June 25, 2002
-----------------------------------------
               Eric D. Sipf

                                               Director                                            June 25, 2002
-----------------------------------------
              David M. Thomas
</TABLE>


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