EXHIBIT 99.1

CONTACTS:

Cubist Pharmaceuticals, Inc.                        Noonan/Russo Communications
Thomas Shea                                         Renee Connolly - media
Vice President & CFO                                (212) 696-4455 ext. 227
(617) 576-4155                                      renee@noonanrusso.com
tshea@cubist.com


              CUBIST PHARMACEUTICALS REPORTS FIRST-QUARTER RESULTS

          COMPANY ANNUAL REPORT NOW AVAILABLE ONLINE AT WWW.CUBIST.COM

CAMBRIDGE, MA, MAY 7, 2001 -- Cubist Pharmaceuticals, Inc. (Nasdaq: CBST) today
reported the results for the first quarter ended March 31, 2001.

Total revenues for the first quarter ended March 31, 2001 were $2,379,000 as
compared to $1,281,000 for the same period in 2000. Total operating expenses for
the quarter ended March 31, 2001 were $20,923,000 as compared to $10,609,000 for
the same period in 2000. The increase in operating expenses is primarily due to
the expenses associated with the expanded development of the Company's
investigational antibiotic Cidecin(TM) (daptomycin for injection) and expanded
headcount. Net loss for the quarter ended March 31, 2001 was $17,603,000 or
($0.63) per share in 2001as compared to a net loss of $8,867,000, or ($0.38) per
share for the same period in 2000.

The Company's cash and investment balance was $135,364,000 on March 31, 2001 and
there were 27,949,797 Common shares outstanding.

"This past quarter was an extremely important one in Cubist's corporate
history," said Scott M. Rocklage, Ph.D., Chairman and Chief Executive Officer of
Cubist. "In mid-March, we announced positive preliminary results from Study
9901, our first completed pivotal Phase III trial for Cidecin, conducted
internationally for the treatment of complicated skin and soft tissue
infections. Shortly thereafter, we presented detailed data demonstrating that
Cidecin had achieved the required endpoint of statistical equivalence to the
comparator agents. The safety profile was similar in both arms of the trial as
well. We are close to completing the U.S. companion study to this trial, and
hope to be able to announce its results along with further findings from Study
9901 later this year."

Dr. Rocklage continued, "We also began implementing our strategic plan to
commercialize Cidecin worldwide. We announced a collaboration with Gilead
Sciences for the European commercialization of Cidecin and oral daptomycin,
following regulatory approval, and announced the hiring of an experienced North
American medical science liaison team to focus on medical education programs and
Cidecin clinical development. As a result of this progress towards
commercialization, combined with our internal expansion, we announced the hiring
of a new President and COO, Dinu Sen, to help manage internal operations and
assess commercialization opportunities for Cidecin in the rest of the world."

"In addition, we achieved two milestones in our corporate collaborations--one
with Novartis in January as a result of the delivery of a second, validated,
novel antiinfective target and screening assay, and another more recently with
Gilead following the successful completion of Study 9901. Throughout the
remainder of 2001," Dr. Rocklage concluded, "we look forward to continued
progress in the Cidecin




clinical program, advancement of our pre-clinical product pipeline and the
continued roll-out of our commercialization strategy for Cidecin."

Separately today, Cubist announced that its 2000 Annual Report is now available
on its corporate website at www.cubist.com. The Company's Form 10-K statement is
available in hard copy and was mailed to all current shareholders on or about
April 25, 2001.

Cubist Pharmaceuticals, Inc. is focused on becoming a global leader in the
research, development and commercialization of novel antimicrobial drugs to
combat serious and life-threatening bacterial and fungal infections. Cubist is
evaluating the safety and efficacy of Cidecin(TM) (daptomycin for injection) in
the EDGE(TM) (Evaluation of Daptomycin against Gram-positive Entities) clinical
trial program and has broadened its pipeline to include multiple pre-clinical
drug candidates. The Company is engaged in strategic partnerships with Novartis
Pharma AG and Merck & Co for the discovery and development of novel
antiinfectives and with Gilead Sciences for the commercialization of daptomycin
in Europe. Cubist is headquartered in Cambridge, MA and has operations in
Vancouver, BC, Canada and Slough, UK.

CUBIST SAFEHARBOR STATEMENT
- ---------------------------
STATEMENTS CONTAINED HEREIN THAT ARE NOT HISTORICAL FACT MAY BE FORWARD-LOOKING
STATEMENTS WITHIN THE MEANING OF SECTION 27A OF THE SECURITIES ACT OF 1933 AND
SECTION 21E OF THE SECURITIES EXCHANGE ACT OF 1934, THAT ARE SUBJECT TO A
VARIETY OF RISKS AND UNCERTAINTIES. THERE ARE A NUMBER OF IMPORTANT FACTORS THAT
COULD CAUSE ACTUAL RESULTS TO DIFFER MATERIALLY FROM THOSE PROJECTED OR
SUGGESTED IN ANY FORWARD-LOOKING STATEMENTS MADE BY THE COMPANY. THESE FACTORS
INCLUDE, BUT ARE NOT LIMITED TO: (i) THE COMPANY'S ABILITY TO SUCCESSFULLY
COMPLETE PRODUCT RESEARCH AND DEVELOPMENT, INCLUDING PRE-CLINICAL AND CLINICAL
STUDIES AND COMMERCIALIZATION; (ii) THE COMPANY'S ABILITY TO OBTAIN REQUIRED
GOVERNMENTAL APPROVALS; (iii) THE COMPANY'S ABILITY TO ATTRACT AND/OR MAINTAIN
MANUFACTURING, SALES, DISTRIBUTION AND MARKETING PARTNERS; AND (iv) THE
COMPANY'S ABILITY TO DEVELOP AND COMMERCIALIZE ITS PRODUCTS BEFORE ITS
COMPETITORS. ADDITIONAL FACTORS THAT WOULD CAUSE ACTUAL RESULTS TO DIFFER
MATERIALLY FROM THOSE PROJECTED OR SUGGESTED IN ANY FORWARD-LOOKING STATEMENTS
ARE CONTAINED IN THE COMPANY'S FILINGS WITH THE SECURITIES AND EXCHANGE
COMMISSION, INCLUDING THOSE FACTORS DISCUSSED UNDER THE CAPTION "RISK FACTORS"
IN THE COMPANY'S ANNUAL REPORT ON FORM 10-K FILED ON APRIL 2, 2001.

                                 (Tables Follow)




                          CUBIST PHARMACEUTICALS, INC.
                            CONDENSED BALANCE SHEETS
                                    UNAUDITED



                                                                    MARCH 31,                      DECEMBER 31,
                                                                      2001                             2000
                                                                -----------------                ----------------
                                                                                           
ASSETS

Cash, cash equivalents and investments                              $135,364,465                     $139,782,817
Property and equipment, net                                           39,281,663                       40,142,080
Other assets                                                          15,029,236                       13,444,953
                                                                -----------------                ----------------

Total assets                                                        $189,675,364                     $193,369,850
                                                                =================                ================


LIABILITIES AND STOCKHOLDERS' EQUITY
Accounts payable                                                      $2,805,709                       $4,541,988
Accrued expenses                                                      11,225,577                        7,424,576
Deferred revenue                                                      14,100,000                        2,500,000
Debt and capital lease obligations                                    45,298,140                       45,883,522
                                                                -----------------                ----------------
Total liabilities                                                     73,429,426                       60,350,086
                                                                -----------------                ----------------

Total stockholders' equity                                           116,245,938                      133,019,764
                                                                -----------------                ----------------

Total liabilities and stockholders' equity                          $189,675,364                     $193,369,850
                                                                =================                ================





                          CUBIST PHARMACEUTICALS, INC.
                       CONDENSED STATEMENTS OF OPERATIONS
                                    UNAUDITED



                                                                            THREE MONTHS ENDED
                                                                                MARCH 31,
                                                            ------------------------------------------------
                                                                     2001                       2000
                                                                     ----                       ----
                                                                                     

Sponsored research revenues                                     $ 2,379,365                $ 1,280,703

Operating expenses:
   Research and development                                      16,413,576                  8,820,012
   General and administrative                                     4,509,746                  1,788,787
                                                            ----------------------     ----------------------
     Total operating expenses                                    20,923,322                 10,608,799

Interest income                                                   2,378,840                    919,396
Interest expense                                                 (1,103,062)                  (458,535)
Other income (expense)                                             (334,474)                        --
                                                            ----------------------     ----------------------

Net loss                                                       $(17,602,653)               $(8,867,235)
                                                            ======================     ======================

Basic and diluted net loss per common share                        ($ 0.63)                   ($ 0.38)
                                                            ======================     ======================
Weighted average number of common shares for basic
   and diluted net loss per common share
                                                                 27,915,084                 23,192,856
                                                            ======================     ======================




       For additional information, visit the Company's Internet website at
                     www.cubist.com or www.noonanrusso.com.



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