8-K

                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON D.C. 20549

                                  ____________


                                    FORM 8-K


                                 CURRENT REPORT
                     Pursuant to Section 13 or 15(d) of the
                         Securities Exchange Act of 1934


Date of report (Date of earliest event reported): October 19, 2004


                              The Medicines Company
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               (Exact Name of Registrant as Specified in Charter)


          Delaware                   000-31191                    04-3324394
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(State or Other Jurisdiction        (Commission                (IRS Employer
     of Incorporation)              File Number)             Identification No.)


             8 Campus Drive
         Parsippany, New Jersey                                07054
 ------------------------------------------                 ------------
  (Address of Principal Executive Offices)                   (Zip Code)

Registrant's telephone number, including area code: (973) 656-1616


- --------------------------------------------------------------------------------
          (Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to
simultaneously satisfy the filing obligation of the registrant under any of the
following provisions (see General Instruction A.2. below):

|_|  Written communications pursuant to Rule 425 under the Securities Act (17
     CFR 230.425)

|_|  Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR
     240.14a-12)

|_|  Pre-commencement communications pursuant to Rule 14d-2(b) under the
     Exchange Act (17 CFR 240.14d-2(b))

|_|  Pre-commencement communications pursuant to Rule 13e-4(c) under the
     Exchange Act (17 CFR 240.13e-4(c))




Item 2.02. Results of Operations and Financial Condition.

     On October 19, 2004, The Medicines Company (the "Company") issued a press
release revising the 2004 financial guidance that the Company had provided in a
press release issued, and on a scheduled conference call held, earlier on
October 19, 2004. The full text of the press release is furnished as Exhibit
99.1 to this Current Report on Form 8-K.

     The information in this Form 8-K (including Exhibit 99.1) shall not be
deemed "filed" for purposes of Section 18 of the Securities Exchange Act of 1934
(the "Exchange Act") or otherwise subject to the liabilities of that section,
nor shall it be deemed incorporated by reference in any filing under the
Securities Act of 1933 or the Exchange Act, except as expressly set forth by
specific reference in such a filing.

Item 9.01. Financial Statements and Exhibits

(c)  Exhibits

     The following exhibit relating to Item 2.02 shall be deemed to be
     furnished, and not filed:

     99.1  Press Release entitled "The Medicines Company Clarifies 2004
           Guidance, Increasing Revenue Forecast" issued by The Medicines
           Company on October 19, 2004.




                                   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.

                                             THE MEDICINES COMPANY


Date: October 20, 2004                       By: /s/ Steven H. Koehler
                                                 ---------------------
                                                 Steven H. Koehler
                                                 Senior Vice President and Chief
                                                 Financial Officer



                                  Exhibit Index


Exhibit No.              Description
- -----------              -----------

   99.1                  Press release dated October 19, 2004 entitled "The
                         Medicines Company Clarifies 2004 Guidance, Increasing
                         Revenue Forecast"

EX-99.1

                                                                    Exhibit 99.1

   The Medicines Company Clarifies 2004 Guidance, Increasing Revenue Forecast

     PARSIPPANY, N.J.--(BUSINESS WIRE)--Oct. 19, 2004--The Medicines Company
(Nasdaq: MDCO) today announced a clarification and adjustment to its financial
guidance as discussed during this evening's conference call. The Company issued
the following guidance to assist investors:

     --   The Company reaffirmed its full year 2004 net earnings estimate of
          $15-19 million.

     --   Total operating expenses (R&D plus S,G&A) were reaffirmed and are
          anticipated to fall in the range of $98-101 million. Cost of revenue
          for the year is expected to be between 20-21% of total revenue.

     --   Revenue for the full year is anticipated to be in the range of
          $139-145 million rather than $139-141 million as discussed on the
          call. Forecasted domestic revenue was reaffirmed to be $135-137
          million, but international revenue is now revised to an estimated to
          be $4-8 million rather than $4-5 million. The variability in potential
          European sales arises from yet to be determined pricing levels in the
          launch markets. European revenue recorded in the third quarter was
          calculated at a contracted initial price, which may be adjusted in the
          fourth quarter based on the end user price.

     The Medicines Company meets the demands of the world's most advanced
medical practitioners by developing products that improve acute hospital care.
The Company markets Angiomax(R) (bivalirudin), an anticoagulant approved in the
U.S. and other countries for use in patients undergoing percutaneous
transluminal coronary angioplasty (PTCA) procedures. The Medicines Company
creates value using its range of clinical and commercial skills to develop
products acquired from leading life science innovators.

     Statements contained in this press release about The Medicines Company, the
Company's projected revenues and financial results, and all other statements
that are not purely historical, may be deemed to be forward-looking statements
for purposes of the safe harbor provisions under The Private Securities
Litigation Reform Act of 1995. Without limiting the foregoing, the words
"believes", "anticipates", plans", "expects", "intends", "potential",
"estimates" and similar expressions are intended to identify forward-looking
statements. These forward-looking statements involve known and unknown risks and
uncertainties that may cause the Company's actual results, levels of activity,
performance or achievements to be materially different from those expressed or
implied by these forward-looking statements. Important factors that may cause or
contribute to such differences include the extent of the commercial success of
Angiomax, physicians' acceptance of Angiomax clinical trial results, whether the
Company will be able to obtain regulatory approval for additional indications of
Angiomax, whether the Company's products will receive approvals from regulatory
agencies, including pricing and reimbursement approvals in certain European
countries, whether the Company's products will advance in the clinical trials
process, and such other factors as are set forth in the risk factors detailed
from time to time in the Company's periodic reports and registration statements
filed with the Securities and Exchange Commission including, without limitation,
the risk factors detailed in the Company's Quarterly Report on Form 10-Q filed
on August 6, 2004, which are incorporated herein by reference. The Company
specifically disclaims any obligation to update these forward-looking
statements.

     CONTACT: The Medicines Company
              Michael Mitchell, 973-656-1616
              investor.relations@themedco.com