8-K/A

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

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

                                   FORM 8-K/A

                                 CURRENT REPORT
                                   Pursuant to
                             Section 13 or 15(d) of

                       THE SECURITIES EXCHANGE ACT OF 1934






         Date of Report (Date of Earliest Event Reported): June 24, 2002

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

                            GENOME THERAPEUTICS CORP.
             (Exact name of registrant as specified in its charter)

        Massachusetts                   0-10824               04-2297484

      (State or other                (Commission           (I.R.S. Employer
jurisdiction of incorporation)       File Number)       Identification Number)



                                100 Beaver Street
                          Waltham, Massachusetts 02453

          (Address, of principal executive offices, including zip code)



                                 (781) 398-2300

               (Registrant's Telephone number including area code)
                              --------------------






                               Page 1 of 5 pages.



ITEM 4.  CHANGE IN REGISTRANT'S CERTIFYING ACCOUNTANT

On June 24, 2002, Genome Therapeutics Corp. (the "Company") dismissed Arthur
Andersen LLP, the firm engaged prior to such dismissal as the Company's
independent public accountant. Also on June 24, 2002, the Company engaged Ernst
& Young LLP as its independent public accountant. The decision to dismiss Arthur
Andersen LLP and engage Ernst & Young LLP as the Company's independent public
accountant was approved by the Company's Audit Committee and the full Board of
Directors.

Arthur Andersen's audit reports on Genome Therapeutics' financial statements for
each of the two most recent fiscal years ended December 31, 2001 and 2000, as
restated, did not contain an adverse opinion or disclaimer of opinion nor were
they qualified or modified as to any uncertainty, audit scope or accounting
principles.

During the periods ended December 31, 2001 and 2000 and the subsequent interim
period ended June 24, 2002, there were no disagreements with Arthur Andersen on
any matter of accounting principles or practices, financial statement disclosure
or auditing scope or procedure, which, if not resolved to the satisfaction or
Arthur Andersen, would have caused them to refer to such disagreement in
connection with their report.

The Company has requested Arthur Andersen LLP to furnish it a letter addressed
to the Commission stating whether it agrees with the above statements. A copy of
that letter, dated June 28, 2002, is filed as Exhibit 16.1 to this Form 8-K/A.
There were no other "reportable events" as that term is described in Item
304(a)(1)(v) of regulation S-K occurring within the Registrant's two most recent
fiscal years and the subsequent interim period ended June 24, 2002.

During Genome Therapeutics' fiscal years ended December 31, 2001 and 2000 and
the subsequent interim period ended June 24, 2002, the Company did not consult
with Ernst & Young LLP with respect to the application of accounting principles
to a specified transaction or the type of audit opinion that might be rendered
on Genome Therapeutics Corp.'s financial statements.

ITEM 7.  FINANCIAL STATEMENTS, PRO FORMA FINANCIAL INFORMATION AND EXHIBITS

         (c) EXHIBITS

             16.1  Letter regarding Change in Certifying Accountant



                                       2



                                   SIGNATURES

     Pursuant to the requirements of the Securities Exchange Act of 1934, the
registrant has duly caused this report to be signed on its behalf by the
undersigned hereunto duly authorized.

                                     GENOME THERAPEUTICS CORP.

                                     By  /s/  Stephen Cohen
                                       --------------------
                                         Name:  Stephen Cohen
                                         Title: Senior Vice President and
                                                  Chief Financial Officer

Date: July 2, 2002




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                                  EXHIBIT INDEX
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Exhibit No.              Description of Exhibits                     Page
- -----------              -----------------------                     ----
   16.1       Letter Regarding Change of Certifying Accountant         5




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EX-16.1

                                                                    Exhibit 16.1

June 28, 2002

Office of the Chief Accountant
Securities and Exchange Commission
450 Fifth Street, N.W.
Washington, D.C. 20549
Fax Number: (202) 942-9656

Dear Sir/Madam:

The representations made in this letter are based solely on discussions with and
representations from the engagement partner and manager on the audits of the
financial statements of this registrant for the two most recent fiscal years.
Those individuals are no longer with Arthur Andersen LLP. We have read the first
4 paragraphs of Item 4 included in the Form 8-K/A dated June 24, 2002 of Genome
Therapeutics, Inc. to be filed with the Securities and Exchange Commission and
have found no basis for disagreement with the statements contained therein.

Very truly yours,

/s/Arthur Andersen LLP

Arthur Andersen LLP

cc: Mr. Stephen Cohen, Chief Financial Officer, Genome Therapeutics, Inc.