<?xml version="1.0"?><ownershipDocument>
    <schemaVersion>X0101</schemaVersion>

    <documentType>4</documentType><periodOfReport>2001-02-27</periodOfReport><notSubjectToSection16>0</notSubjectToSection16>
    <issuer>
        <issuerCik>0000892025</issuerCik>
        <issuerName>MARTEK BIOSCIENCES CORP</issuerName>
        <issuerTradingSymbol>MATK</issuerTradingSymbol></issuer><reportingOwner><reportingOwnerId>
            <rptOwnerCik>0001176268</rptOwnerCik>
            <rptOwnerName>PANEM SANDRA PHD</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>  </rptOwnerStreet1>
            <rptOwnerStreet2>  </rptOwnerStreet2>
            <rptOwnerCity>  </rptOwnerCity>
            <rptOwnerState>  </rptOwnerState>
            <rptOwnerZipCode>  </rptOwnerZipCode>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>1</isDirector><isOfficer>0</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther></reportingOwnerRelationship></reportingOwner><nonDerivativeSecurity><securityTitle><value>Common Stock</value></securityTitle><transactionDate><value>2001-02-27</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>P</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionTimeliness><value></value></transactionTimeliness><transactionAmounts><transactionShares><value>377953</value><footnoteId id="F2" /></transactionShares><transactionValue><value>15.875</value><footnoteId id="F1" /></transactionValue><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>377953</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>Cross Atlantic</value><footnoteId id="F2" /><footnoteId id="F3" /></natureOfOwnership></ownershipNature></nonDerivativeSecurity><nonDerivativeSecurity><securityTitle><value>Common Stock</value></securityTitle><transactionDate><value>2003-06-20</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>X</transactionCode><equitySwapInvolved>0</equitySwapInvolved><footnoteId id="F4" /></transactionCoding><transactionTimeliness><value></value></transactionTimeliness><transactionAmounts><transactionShares><value>7874</value></transactionShares><transactionValue><value>19.05</value></transactionValue><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>259826</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>Cross Atlantic</value><footnoteId id="F5" /></natureOfOwnership></ownershipNature></nonDerivativeSecurity><nonDerivativeSecurity><securityTitle><value>Common Stock</value></securityTitle><transactionDate><value>2003-06-20</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>J</transactionCode><equitySwapInvolved>0</equitySwapInvolved><footnoteId id="F4" /></transactionCoding><transactionTimeliness><value></value></transactionTimeliness><transactionAmounts><transactionShares><value>7874</value></transactionShares><transactionValue><value>0</value><footnoteId id="F4" /></transactionValue><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>251952</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>Cross Atlantic</value><footnoteId id="F5" /></natureOfOwnership></ownershipNature></nonDerivativeSecurity><nonDerivativeSecurity><securityTitle><value>Common Stock</value></securityTitle><transactionDate><value>2003-06-20</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>J</transactionCode><equitySwapInvolved>0</equitySwapInvolved><footnoteId id="F4" /></transactionCoding><transactionTimeliness><value></value></transactionTimeliness><transactionAmounts><transactionShares><value>20</value></transactionShares><transactionValue><value>0</value><footnoteId id="F4" /></transactionValue><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>7631</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership></ownershipNature></nonDerivativeSecurity><derivativeSecurity><securityTitle><value>Common Stock Warrants (right to buy)</value></securityTitle><conversionOrExercisePrice><value>19.05</value></conversionOrExercisePrice><transactionDate><value>2001-02-27</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>P</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionTimeliness><value></value></transactionTimeliness><transactionAmounts><transactionShares><value>94489</value></transactionShares><transactionValue><value>0</value><footnoteId id="F1" /></transactionValue><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><value>2001-02-27</value></exerciseDate><expirationDate><value>2006-03-02</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>94489</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>94489</value><footnoteId id="F5" /></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>Cross Atlantic</value><footnoteId id="F5" /></natureOfOwnership></ownershipNature></derivativeSecurity><derivativeSecurity><securityTitle><value>Common Stock Warrants (right to buy)</value></securityTitle><conversionOrExercisePrice><value>19.05</value></conversionOrExercisePrice><transactionDate><value>2003-06-20</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>X</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionTimeliness><value></value></transactionTimeliness><transactionAmounts><transactionShares><value>7874</value></transactionShares><transactionValue><value>0</value><footnoteId id="F1" /></transactionValue><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><value>2001-02-27</value></exerciseDate><expirationDate><value>2006-03-02</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>7874</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>86615</value><footnoteId id="F5" /></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>Cross Atlantic</value><footnoteId id="F5" /></natureOfOwnership></ownershipNature></derivativeSecurity><footnotes><footnote id="F1">The purchase price of $15.8750 is the price per unit consisting of one share of common stock and the right to purchase one quarter (1/4) of a share of Martek common stock.</footnote><footnote id="F2">Upon the closing of the February 27, 2001 private placement, the Cross Atlantic entities acquired an aggregate of 377,953 shares of Martek common stock and warrants to purchase 94,489 shares of Martek common stock.  The Cross Atlantic entities are each managed by Cross Atlantic Partners Inc. and CAP Advisors Services, LLC.  Dr. Panem is an officer in Cross Atlantic Partners Inc. and a member of Cap Advisors Services, LLC.  Dr. Panem disclaims beneficial ownership of the Martek common stock and warrants held by the Cross Atlantic entities except to the extent of her pecuniary interest therein.</footnote><footnote id="F3">On April 1, 2002, the Cross Atlantic entities did a pro rata distribution for which no consideration was received to its general and limited partners.  The total amount of the distribution was 33,634  with Dr. Panem receiving 594 shares in the distribution.  On May 16, 2003, the Cross Atlantic entities did a pro rata distribution for which no consideration was received to its general and limited partners.  The total shares distributed was 92,367 with Dr. Panem receiving 1,419 shares in the distribution.</footnote><footnote id="F4">On June 20, 2003, Cross Atlantic Partners I, K/S exercised a warrant to purchase 7,874 shares of Martek common stock.  Following the exercise of the warrant, Cross Atlantic Partners I, K/S did a pro rata distribution for which no consideration was received to its general and limited partners.</footnote><footnote id="F5">The share number in column 5 represents the aggregate holdings of the Cross Atlantic entities, which comprise of Cross Atlantic Partners I, K/S (Cross Atlantic I), Cross Atlantic Partners II, K/S (Cross Atlantic II), Cross Atlantic Partners III, K/S (Cross Atlantic III), Cross Atlantic Partners IV, K/S (Cross Atlantic IV).  As previously stated, Dr. Panem disclaims beneficial ownership of the Martek common stock and warrants convertible into Martek common stock held by these entities except to the extent of her pecuniary interest therein.  After the transaction described herein, Cross Atlantic I owns no shares of Martek common stock or warrants; Cross Atlantic II owns 36,647 shares of Martek common stock and 12,599 warrants; Cross Atlantic III owns 123,687 shares of Martek common stock and 42,520 warrants; Cross Atlantic IV owns 91,618 shares of Martek common stock and 31,496 warrants.</footnote></footnotes><ownerSignature><signatureName>/s/George P. Barker
George P. Barker, by Power of Atty.</signatureName><signatureDate>2003-07-21</signatureDate></ownerSignature></ownershipDocument>

