Exhibit 99.1


FOR IMMEDIATE RELEASE

              GENOME THERAPEUTICS ADDS SCHERING-PLOUGH AS CUSTOMER
                            TO GTC SEQUENCING CENTER

Waltham, Mass., June 16, 2000 -- Genome Therapeutics Corp. (Nasdaq: GENE), a
leading genomics company, today announced a contract with Schering-Plough
Corporation (NYSE: SGP) to provide DNA sequencing information.

As part of the contract, Genome Therapeutics will generate high-quality DNA
sequence information in support of gene discovery projects at Schering-Plough.
Genome Therapeutics will employ its proprietary sequencing techniques,
automation, bioinformatics and quality control procedures to generate sequence
reads and provide analysis of the sequenced regions.

"Schering-Plough has been a leader in utilizing the power of genomics to expand
its drug discovery pipeline since the mid-1990s," said Richard D. Gill, Ph.D.,
President and COO of Genome Therapeutics. "We are pleased to expand our current
relationship with Schering-Plough by conducting specialized sequencing to
advance its drug discovery efforts, and view this contract as further validation
of the quality of our sequencing operations."

Launched in 1999, the GTC Sequencing Center is recognized as a leading source of
genomic sequencing, commercializing a core technology that has been the basis
for its alliances with several pharmaceutical and biotech partners. Customers to
the GTC Sequencing Center include Astra-Zeneca, Aventis, Biogen, Cubist, the
Human Genome Project and the Mouse Genome Sequencing Network. The range of
services provided to the customers includes genomic sequencing, cDNA and PCR
sequencing, variation detection and specialized sequencing.

This sequencing agreement builds upon the established human and infectious
disease genomics alliances between Genome Therapeutics and Schering-Plough. The
companies have ongoing research alliances to identify together new treatments
for asthma, novel antibacterial agents against drug-resistant organisms, and new
pharmaceutical products to prevent and treat fungal infections. In addition,
Schering-Plough is a subscriber to the PathoGenome(TM) Database, a non-exclusive
database that provides DNA sequence information for medically relevant microbial
organisms.

Genome Therapeutics (www.genomecorp.com) is a leader in the commercialization of
genomics-based drug discovery. The Company's gene discovery strategy is to
identify and characterize human genes associated with major diseases and
elucidate microbial genes as novel drug targets against many serious infectious
organisms. Together with its strategic partners, including Schering-Plough,
AstraZeneca, Wyeth-Ayerst and bioMerieux, Genome Therapeutics is using genomic
information to develop a new generation of genomics-based pharmaceutical,
vaccine and diagnostic products.

Statements in this press release that are not strictly historical are "forward
looking" statements as defined in the Private Securities Litigation Reform Act
of 1995. A number of important factors could cause actual results to differ
materially from those projected or suggested in the forward looking statement
including, but not limited to, the ability of the Company and its alliance
partners to (i) successfully develop products based on the Company's genomic
information, (ii) obtain the necessary governmental approvals, (iii) effectively
commercialize any products developed before its competitors and (iv) obtain and
enforce intellectual property rights, as well as the risk factors described in
the Company's Annual Report on Form 10-K.


             Contacts:
             Christopher Taylor                       Douglas MacDougall
             Director of Investor Relations           Vice President
             Genome Therapeutics Corp.                Feinstein Kean Healthcare
             (781) 398-2466                           (617) 577-8110






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