FILED PURSUANT TO RULE 424(b)(5)
                               FILE NO. 333-32614

PRICING SUPPLEMENT NO. 4 DATED JULY 7, 2000 (TO PROSPECTUS DATED JUNE 21, 2000).
                                 373,000 SHARES
                           GENOME THERAPEUTICS CORP.
                                  COMMON STOCK

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    On July 5, 2000, we sold 148,000 shares of our common stock, par value
$0.10 per share (the "Common Stock"), at a weighted average price of
$30.4101 per share. On July 7, 2000, we sold 225,000 shares of Common Stock at a
weighted average price of $27.0269 per share. Each of these sales was conducted
through our agent, Tucker Anthony Incorporated, in transactions effected through
the Nasdaq National Market.

                                                           
Gross Proceeds to Genome Therapeutics Corp. ................  $10,581,747.00
Commission to Tucker Anthony................................  $   211,709.00
Net Proceeds to Genome Therapeutics Corp. ..................  $10,370,038.00
On July 7, 2000 the last reported sales price of the Common
  Stock on the Nasdaq National Market was...................  $        26.00



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Neither the Securities and Exchange Commission nor any state securities
commission has approved or disapproved of these securities or determined if this
prospectus is truthful or complete. Any representation to the contrary is a
criminal offense.