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):  April 20, 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
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     (Address of Principal Executive Offices)                  (Zip Code)

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



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






Item 12.  Disclosure of Results of Operations and Financial Condition.

         On April 20, 2004, The Medicines Company (the "Company") announced its
financial results for the quarter ended March 31, 2004. The full text of the
press release issued in connection with the announcement is attached as Exhibit
99.1 to this Current Report on Form 8-K.

         The information in this Current Report on Form 8-K and the Exhibit
attached hereto 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.








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






                                  Exhibit Index


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

99.1                    Press release dated April 20, 2004 entitled "The
                        Medicines Company Reports First Quarter 2004
                        Financial Results."