<?xml version="1.0"?>
<ownershipDocument>
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            <rptOwnerState>  </rptOwnerState>
            <rptOwnerZipCode>  </rptOwnerZipCode>
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		<postTransactionAmounts>
			<sharesOwnedFollowingTransaction>
				<value>0</value>
			</sharesOwnedFollowingTransaction>
		</postTransactionAmounts>
		<ownershipNature>
			<directOrIndirectOwnership>
				<value>D</value>
			</directOrIndirectOwnership>
			<natureOfOwnership>
				<value/>
			</natureOfOwnership>
		</ownershipNature>
	</derivativeSecurity>
	<derivativeSecurity>
		<securityTitle>
			<value>Molecular Oncology DOP Stock Option (right to buy)</value>
		</securityTitle>
		<conversionOrExercisePrice>
			<value>2.58</value>
		</conversionOrExercisePrice>
		<transactionDate>
			<value>2003-06-30</value>
		</transactionDate>
		<transactionCoding>
			<transactionFormType>4</transactionFormType>
			<transactionCode>J</transactionCode>
			<equitySwapInvolved>0</equitySwapInvolved>
		</transactionCoding>
		<transactionAmounts>
			<transactionShares>
				<value>18000</value>
				<footnoteId id="F1"/>
			</transactionShares>
			<transactionValue>
				<value>0</value>
			</transactionValue>
			<transactionAcquiredDisposedCode>
				<value>D</value>
			</transactionAcquiredDisposedCode>
		</transactionAmounts>
		<exerciseDate>
			<value>2004-05-29</value>
			<footnoteId id="F2"/>
		</exerciseDate>
		<expirationDate>
			<value>2013-05-29</value>
		</expirationDate>
		<underlyingSecurity>
			<underlyingSecurityTitle>
				<value>Genzyme Molecular Oncology common stock (GZMO)</value>
			</underlyingSecurityTitle>
			<underlyingSecurityShares>
				<value>18000</value>
			</underlyingSecurityShares>
		</underlyingSecurity>
		<postTransactionAmounts>
			<sharesOwnedFollowingTransaction>
				<value>0</value>
			</sharesOwnedFollowingTransaction>
		</postTransactionAmounts>
		<ownershipNature>
			<directOrIndirectOwnership>
				<value>D</value>
			</directOrIndirectOwnership>
			<natureOfOwnership>
				<value/>
			</natureOfOwnership>
		</ownershipNature>
	</derivativeSecurity>
	<footnotes>
		<footnote id="F1">On June 30, 2003 in relation to the elimination of Genzyme's tracking stock structure, all stock options of Genzyme Biosurgery and Genzyme Molecular were exchanged for stock options of Genzyme General.  The exchange ratio was based on the closing prices of all three stocks on 6/30/03.  Genzyme Biosurgery options were exchanged at a rate of .04945 and Genzyme Molecular Oncology options were exchanged at a rate of .05614.</footnote>
		<footnote id="F2">Options vest in 1/3 annual increments on the dates of the next three annual meetings of shareholders following the original date of grant.</footnote>
		<footnote id="F3">Options vest in 50% increments on May 31, 2002 and May 31, 2003.</footnote>
	</footnotes>
	<ownerSignature>
		<signatureName>By: Susan P. Cogswell, Attorney-in-Fact</signatureName>
		<signatureDate>2003-07-01</signatureDate>
	</ownerSignature>
</ownershipDocument>
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2003-06-30
0
0000732485
GENZYME CORP
GENZ
0001136998
MCGILLICUDY CORNELIUS III
1
0
0
0
Biosurgery DOP stock option (right to buy)
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4
J
0
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D
2001-05-31
2011-02-12
Genzyme Biosurgery common stock (GZBX)
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0
D
Biosurgery DOP stock option (right to buy)
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4
J
0
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0
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2003-05-31
2011-02-12
Genzyme Biosurgery common stock (GZBX)
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0
D
Biosurgery DOP stock option (right to buy)
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2003-06-30
4
J
0
4000
0
D
2003-05-31
2011-05-31
Genzyme Biosurgery common stock (GZBX)
4000
0
D
Biosurgery DOP Stock Option (right to buy)
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2003-06-30
4
J
0
18000
0
D
2004-05-29
2013-05-29
Genzyme Biosurgery common stock (GZBX)
18000
0
D
Genzyme General DOP stock option (right to buy)
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2003-06-30
4
J
0
400
0
A
2001-05-31
2011-02-12
Genzyme General common stock (GENZ)
400
400
D
Genzyme General DOP stock option (right to buy)
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2003-06-30
4
J
0
193
0
A
2001-05-31
2011-02-12
Genzyme General common stock (GENZ)
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193
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Genzyme General DOP stock option (right to buy)
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2003-06-30
4
J
0
673
0
A
2001-05-31
2011-02-12
Genzyme General common stock (GENZ)
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673
D
Genzyme General DOP stock option (right to buy)
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2003-06-30
4
J
0
197
0
A
2002-05-31
2011-05-31
Genzyme General common stock (GENZ)
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197
D
Genzyme General DOP stock option (right to buy)
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2003-06-30
4
J
0
224
0
A
2002-05-31
2011-05-31
Genzyme General common stock (GENZ)
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224
D
Genzyme General DOP stock option (right to buy)
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2003-06-30
4
J
0
890
0
A
2004-05-29
2013-05-29
Genzyme General common stock (GENZ)
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890
D
Genzyme General DOP stock option (right to buy)
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2003-06-30
4
J
0
1010
0
A
2004-05-29
2013-05-29
Genzyme General common stock (GENZ)
1010
1010
D
Molecular Oncology DOP stock option (right to buy)
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2003-06-30
4
J
0
12000
0
D
2001-05-31
2011-02-12
Genzyme Molecular Oncology common stock (GZMO)
12000
0
D
Molecular Oncology DOP stock option (right to buy)
15.40
2003-06-30
4
J
0
4000
0
D
2002-05-31
2011-05-31
Genzyme Molecular Oncology common stock (GZMO)
4000
0
D
Molecular Oncology DOP Stock Option (right to buy)
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2003-06-30
4
J
0
18000
0
D
2004-05-29
2013-05-29
Genzyme Molecular Oncology common stock (GZMO)
18000
0
D
On June 30, 2003 in relation to the elimination of Genzyme's tracking stock structure, all stock options of Genzyme Biosurgery and Genzyme Molecular were exchanged for stock options of Genzyme General.  The exchange ratio was based on the closing prices of all three stocks on 6/30/03.  Genzyme Biosurgery options were exchanged at a rate of .04945 and Genzyme Molecular Oncology options were exchanged at a rate of .05614.
Options vest in 1/3 annual increments on the dates of the next three annual meetings of shareholders following the original date of grant.
Options vest in 50% increments on May 31, 2002 and May 31, 2003.
By: Susan P. Cogswell, Attorney-in-Fact
2003-07-01