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Proc-Type: 2001,MIC-CLEAR
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<SEC-DOCUMENT>0000732485-03-000071.txt : 20031217
<SEC-HEADER>0000732485-03-000071.hdr.sgml : 20031217
<ACCEPTANCE-DATETIME>20031217152219
ACCESSION NUMBER:		0000732485-03-000071
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20031217
FILED AS OF DATE:		20031217

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			GENZYME CORP
		CENTRAL INDEX KEY:			0000732485
		STANDARD INDUSTRIAL CLASSIFICATION:	BIOLOGICAL PRODUCTS (NO DIAGNOSTIC SUBSTANCES) [2836]
		IRS NUMBER:				061047163
		STATE OF INCORPORATION:			MA
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		ONE KENDALL SQ
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02139
		BUSINESS PHONE:		6172527500

	MAIL ADDRESS:	
		STREET 1:		ONE KENDALL SQUARE
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02139

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			VAN HEEK G JAN
		CENTRAL INDEX KEY:			0001021040
		STANDARD INDUSTRIAL CLASSIFICATION:	BIOLOGICAL PRODUCTS (NO DIAGNOSTIC SUBSTANCES) [2836]
		STATE OF INCORPORATION:			MA
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	333-90510
		FILM NUMBER:		031059978

	BUSINESS ADDRESS:	
		STREET 1:		C/O GENZYME CORP
		STREET 2:		ONE KENDALL SQ
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02139
		BUSINESS PHONE:		6172527500

	MAIL ADDRESS:	
		STREET 1:		ONE KENDALL SQUARE
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02139
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>van99.xml
<TEXT>
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					<value>47.41</value>
				</transactionPricePerShare>
				<transactionAcquiredDisposedCode>
					<value>D</value>
				</transactionAcquiredDisposedCode>
			</transactionAmounts>
			<postTransactionAmounts>
				<sharesOwnedFollowingTransaction>
					<value>26271</value>
				</sharesOwnedFollowingTransaction>
			</postTransactionAmounts>
			<ownershipNature>
				<directOrIndirectOwnership>
					<value>I</value>
				</directOrIndirectOwnership>
				<natureOfOwnership>
					<value>By Spouse</value>
				</natureOfOwnership>
			</ownershipNature>
		</nonDerivativeTransaction>
		<nonDerivativeTransaction>
			<securityTitle>
				<value>Genzyme General common stock (GENZ)</value>
			</securityTitle>
			<transactionDate>
				<value>2003-12-17</value>
			</transactionDate>
			<deemedExecutionDate>
			</deemedExecutionDate>
			<transactionCoding>
				<transactionFormType>4</transactionFormType>
				<transactionCode>S</transactionCode>
				<equitySwapInvolved>0</equitySwapInvolved>
			</transactionCoding>
			<transactionAmounts>
				<transactionShares>
					<value>1200</value>
				</transactionShares>
				<transactionPricePerShare>
					<value>47.43</value>
				</transactionPricePerShare>
				<transactionAcquiredDisposedCode>
					<value>D</value>
				</transactionAcquiredDisposedCode>
			</transactionAmounts>
			<postTransactionAmounts>
				<sharesOwnedFollowingTransaction>
					<value>25071</value>
				</sharesOwnedFollowingTransaction>
			</postTransactionAmounts>
			<ownershipNature>
				<directOrIndirectOwnership>
					<value>I</value>
				</directOrIndirectOwnership>
				<natureOfOwnership>
					<value>By Spouse</value>
				</natureOfOwnership>
			</ownershipNature>
		</nonDerivativeTransaction>
		<nonDerivativeTransaction>
			<securityTitle>
				<value>Genzyme General common stock (GENZ)</value>
			</securityTitle>
			<transactionDate>
				<value>2003-12-17</value>
			</transactionDate>
			<deemedExecutionDate>
			</deemedExecutionDate>
			<transactionCoding>
				<transactionFormType>4</transactionFormType>
				<transactionCode>S</transactionCode>
				<equitySwapInvolved>0</equitySwapInvolved>
			</transactionCoding>
			<transactionAmounts>
				<transactionShares>
					<value>100</value>
				</transactionShares>
				<transactionPricePerShare>
					<value>47.45</value>
				</transactionPricePerShare>
				<transactionAcquiredDisposedCode>
					<value>D</value>
				</transactionAcquiredDisposedCode>
			</transactionAmounts>
			<postTransactionAmounts>
				<sharesOwnedFollowingTransaction>
					<value>24971</value>
				</sharesOwnedFollowingTransaction>
			</postTransactionAmounts>
			<ownershipNature>
				<directOrIndirectOwnership>
					<value>I</value>
				</directOrIndirectOwnership>
				<natureOfOwnership>
					<value>By Spouse</value>
				</natureOfOwnership>
			</ownershipNature>
		</nonDerivativeTransaction>
		<nonDerivativeTransaction>
			<securityTitle>
				<value>Genzyme General common stock (GENZ)</value>
			</securityTitle>
			<transactionDate>
				<value>2003-12-17</value>
			</transactionDate>
			<deemedExecutionDate>
			</deemedExecutionDate>
			<transactionCoding>
				<transactionFormType>4</transactionFormType>
				<transactionCode>S</transactionCode>
				<equitySwapInvolved>0</equitySwapInvolved>
			</transactionCoding>
			<transactionAmounts>
				<transactionShares>
					<value>500</value>
				</transactionShares>
				<transactionPricePerShare>
					<value>47.50</value>
				</transactionPricePerShare>
				<transactionAcquiredDisposedCode>
					<value>D</value>
				</transactionAcquiredDisposedCode>
			</transactionAmounts>
			<postTransactionAmounts>
				<sharesOwnedFollowingTransaction>
					<value>24471</value>
				</sharesOwnedFollowingTransaction>
			</postTransactionAmounts>
			<ownershipNature>
				<directOrIndirectOwnership>
					<value>I</value>
				</directOrIndirectOwnership>
				<natureOfOwnership>
					<value>By Spouse</value>
				</natureOfOwnership>
			</ownershipNature>
		</nonDerivativeTransaction>
		<nonDerivativeTransaction>
			<securityTitle>
				<value>Genzyme General common stock (GENZ)</value>
			</securityTitle>
			<transactionDate>
				<value>2003-12-17</value>
			</transactionDate>
			<deemedExecutionDate>
			</deemedExecutionDate>
			<transactionCoding>
				<transactionFormType>4</transactionFormType>
				<transactionCode>S</transactionCode>
				<equitySwapInvolved>0</equitySwapInvolved>
			</transactionCoding>
			<transactionAmounts>
				<transactionShares>
					<value>100</value>
				</transactionShares>
				<transactionPricePerShare>
					<value>47.52</value>
				</transactionPricePerShare>
				<transactionAcquiredDisposedCode>
					<value>D</value>
				</transactionAcquiredDisposedCode>
			</transactionAmounts>
			<postTransactionAmounts>
				<sharesOwnedFollowingTransaction>
					<value>24371</value>
				</sharesOwnedFollowingTransaction>
			</postTransactionAmounts>
			<ownershipNature>
				<directOrIndirectOwnership>
					<value>I</value>
				</directOrIndirectOwnership>
				<natureOfOwnership>
					<value>By Spouse</value>
				</natureOfOwnership>
			</ownershipNature>
		</nonDerivativeTransaction>
		<nonDerivativeHolding>
			<securityTitle>
				<value>Genzyme General common stock (GENZ)</value>
			</securityTitle>
			<postTransactionAmounts>
				<sharesOwnedFollowingTransaction>
					<value>4294</value>
				</sharesOwnedFollowingTransaction>
			</postTransactionAmounts>
			<ownershipNature>
				<directOrIndirectOwnership>
					<value>D</value>
				</directOrIndirectOwnership>
				<natureOfOwnership>
					<value/>
				</natureOfOwnership>
			</ownershipNature>
		</nonDerivativeHolding>
		<nonDerivativeHolding>
			<securityTitle>
				<value>Genzyme General common stock (GENZ)</value>
			</securityTitle>
			<postTransactionAmounts>
				<sharesOwnedFollowingTransaction>
					<value>816</value>
				</sharesOwnedFollowingTransaction>
			</postTransactionAmounts>
			<ownershipNature>
				<directOrIndirectOwnership>
					<value>I</value>
				</directOrIndirectOwnership>
				<natureOfOwnership>
					<value>By 401(k)</value>
				</natureOfOwnership>
			</ownershipNature>
		</nonDerivativeHolding>
		<nonDerivativeHolding>
			<securityTitle>
				<value>Genzyme General common stock (GENZ)</value>
			</securityTitle>
			<postTransactionAmounts>
				<sharesOwnedFollowingTransaction>
					<value>1665</value>
				</sharesOwnedFollowingTransaction>
			</postTransactionAmounts>
			<ownershipNature>
				<directOrIndirectOwnership>
					<value>I</value>
				</directOrIndirectOwnership>
				<natureOfOwnership>
					<value>By 401(k) by spouse</value>
				</natureOfOwnership>
			</ownershipNature>
		</nonDerivativeHolding>
	</nonDerivativeTable>
	<derivativeTable>
		<derivativeTransaction>
			<securityTitle>
				<value>Genzyme General NQ Stock Option (right to buy)</value>
			</securityTitle>
			<conversionOrExercisePrice>
				<value>46.24</value>
			</conversionOrExercisePrice>
			<transactionDate>
				<value>2003-12-17</value>
			</transactionDate>
			<deemedExecutionDate>
			</deemedExecutionDate>
			<transactionCoding>
				<transactionFormType>4</transactionFormType>
				<transactionCode>M</transactionCode>
				<equitySwapInvolved>0</equitySwapInvolved>
			</transactionCoding>
			<transactionAmounts>
				<transactionShares>
					<value>10800</value>
				</transactionShares>
				<transactionPricePerShare>
					<value>0</value>
				</transactionPricePerShare>
				<transactionAcquiredDisposedCode>
					<value>D</value>
				</transactionAcquiredDisposedCode>
			</transactionAmounts>
			<exerciseDate>
				<value>2003-05-29</value>
				<footnoteId id="F1"/>
			</exerciseDate>
			<expirationDate>
				<value>2013-05-29</value>
			</expirationDate>
			<underlyingSecurity>
				<underlyingSecurityTitle>
					<value>Genzyme General common stock (GENZ)</value>
				</underlyingSecurityTitle>
				<underlyingSecurityShares>
					<value>10800</value>
				</underlyingSecurityShares>
			</underlyingSecurity>
			<postTransactionAmounts>
				<sharesOwnedFollowingTransaction>
					<value>0</value>
				</sharesOwnedFollowingTransaction>
			</postTransactionAmounts>
			<ownershipNature>
				<directOrIndirectOwnership>
					<value>I</value>
				</directOrIndirectOwnership>
				<natureOfOwnership>
					<value>By Spouse</value>
				</natureOfOwnership>
			</ownershipNature>
		</derivativeTransaction>
		<derivativeHolding>
			<securityTitle>
				<value>Genzyme General NQ Stock Option (right to buy)</value>
			</securityTitle>
			<conversionOrExercisePrice>
				<value>46.24</value>
			</conversionOrExercisePrice>
			<exerciseDate>
				<value>2003-05-29</value>
			</exerciseDate>
			<expirationDate>
				<value>2013-05-29</value>
			</expirationDate>
			<underlyingSecurity>
				<underlyingSecurityTitle>
					<value>Genzyme General common stock (GENZ)</value>
				</underlyingSecurityTitle>
				<underlyingSecurityShares>
					<value>90000</value>
				</underlyingSecurityShares>
			</underlyingSecurity>
			<postTransactionAmounts>
				<sharesOwnedFollowingTransaction>
					<value>90000</value>
				</sharesOwnedFollowingTransaction>
			</postTransactionAmounts>
			<ownershipNature>
				<directOrIndirectOwnership>
					<value>D</value>
				</directOrIndirectOwnership>
				<natureOfOwnership>
					<value/>
				</natureOfOwnership>
			</ownershipNature>
		</derivativeHolding>
	</derivativeTable>
	<footnotes>
		<footnote id="F1">Options vest in 20% annual increments beginning on the original date of grant.</footnote>
	</footnotes>
	<remarks>
	</remarks>
	<ownerSignature>
		<signatureName>By: Susan P. Cogswell, Attorney-in-Fact</signatureName>
		<signatureDate>2003-12-17</signatureDate>
	</ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----