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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,
 I7kQeJWz9AxQImPyDRuUS9c7rgnzOBzh8WfrCPNdZQSvekiuYWN5VDJg2fFIFn2X
 a9g9s5b1CKtJQBO+f0cK+w==

<SEC-DOCUMENT>0000873591-05-000013.txt : 20050218
<SEC-HEADER>0000873591-05-000013.hdr.sgml : 20050218
<ACCEPTANCE-DATETIME>20050218145249
ACCESSION NUMBER:		0000873591-05-000013
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20050216
FILED AS OF DATE:		20050218
DATE AS OF CHANGE:		20050218

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MEDIMMUNE INC /DE
		CENTRAL INDEX KEY:			0000873591
		STANDARD INDUSTRIAL CLASSIFICATION:	BIOLOGICAL PRODUCTS (NO DIAGNOSTIC SUBSTANCES) [2836]
		IRS NUMBER:				521555759
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		35 W WATKINS MILL RD
		CITY:			GAITHERSBURG
		STATE:			MD
		ZIP:			20878
		BUSINESS PHONE:		3014170770

	MAIL ADDRESS:	
		STREET 1:		35 W WATKINS MILL ROAD
		CITY:			GAITHERSBURG
		STATE:			MD
		ZIP:			20878

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			MOTT DAVID M
		CENTRAL INDEX KEY:			0001219871

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-19131
		FILM NUMBER:		05627111

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		3014170770

	MAIL ADDRESS:	
		STREET 1:		35 W WATKINS MILL ROAD
		CITY:			GAITHERSBURG
		STATE:			MD
		ZIP:			20878
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2005-02-16</periodOfReport>

    <issuer>
        <issuerCik>0000873591</issuerCik>
        <issuerName>MEDIMMUNE INC /DE</issuerName>
        <issuerTradingSymbol>MEDI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001219871</rptOwnerCik>
            <rptOwnerName>MOTT DAVID M</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>ONE MEDIMMUNE WAY</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>GAITHERSBURG</rptOwnerCity>
            <rptOwnerState>MD</rptOwnerState>
            <rptOwnerZipCode>20878</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Vice Chairman, CEO &amp; President</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable></nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Options (Right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>24.17</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2005-02-16</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>600000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2005-05-16</value>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2015-02-16</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>600000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>600000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">This grant is exercisable in quarterly installments over four years.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>By Power of Attorney: Timothy Pearson</signatureName>
        <signatureDate>2005-02-17</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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