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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 VZ2wN6zR7iwaRE3YGb7Dmiw3nUCtWwGq1YIXVW7fvBsxqmU7YJzjtukJ9R5+CzaE
 7/faWqmBBzxCgAXMvMMuIQ==

<SEC-DOCUMENT>0001179110-05-011091.txt : 20050611
<SEC-HEADER>0001179110-05-011091.hdr.sgml : 20050611
<ACCEPTANCE-DATETIME>20050526174101
ACCESSION NUMBER:		0001179110-05-011091
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20050525
FILED AS OF DATE:		20050526
DATE AS OF CHANGE:		20050526

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MEDICINES CO /DE
		CENTRAL INDEX KEY:			0001113481
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				043324394
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		8 CAMPUS DRIVE
		CITY:			PARSIPPANY
		STATE:			NJ
		ZIP:			07054
		BUSINESS PHONE:		973-656-1616

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	MEDICINES CO/ MA
		DATE OF NAME CHANGE:	20000504

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			KESSLER ARMIN M
		CENTRAL INDEX KEY:			0001194185

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-31191
		FILM NUMBER:		05861088

	BUSINESS ADDRESS:	
		STREET 1:		157 TECHNOLGY DRIVE
		CITY:			IRVINE
		STATE:			TX
		ZIP:			92618
		BUSINESS PHONE:		9497996700
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>FORM 4 -
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2005-05-25</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001113481</issuerCik>
        <issuerName>MEDICINES CO /DE</issuerName>
        <issuerTradingSymbol>MDCO</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001194185</rptOwnerCik>
            <rptOwnerName>KESSLER ARMIN M</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>THE MEDICINES COMPANY</rptOwnerStreet1>
            <rptOwnerStreet2>8 CAMPUS DRIVE</rptOwnerStreet2>
            <rptOwnerCity>PARSIPPANY</rptOwnerCity>
            <rptOwnerState>NJ</rptOwnerState>
            <rptOwnerZipCode>07054</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable></nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Option (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>21.45</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2005-05-25</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>15000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2015-05-25</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>15000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>15000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">This option vests in 12 equal monthly installments beginning on June 25, 2005.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Armin M. Kessler</signatureName>
        <signatureDate>2005-05-25</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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