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Exhibit 12.1

GENZYME CORPORATION AND SUBSIDIARIES
Computation of Ratio of Earnings to Fixed Charges
(Amounts in Thousands)

																	Six Months Ended June 30, 2005
			Year Ended December 31,
			2000			2001			2002		2003			2004
Income (loss) before income taxes			$	(7,462	)	$	(118,343	)	$	104,211	$	5,055		$	227,696		$	315,714
Add: equity in loss of equity method investments				44,965			35,681			16,858		16,743			15,624			2,135
Deduct: minority interest				(4,625	)		(2,259	)		—		(2,232	)		(5,999	)		(5,551	)
Income (loss) before income taxes, equity in loss of equity method investments and minority interest				32,878			(84,921	)		121,069		19,566			237,321			312,298
Add:
	Fixed charges:
		Portion of rents representative of the interest factor		9,233			11,233			11,833		15,233			15,233			7,617
		Amortization of debt issuance costs(1)		1,148			2,638			2,964		3,311			10,205			1,912
		Interest expense		14,562			34,495			24,188		23,289			28,022			6,362
	Amortization of capitalized interest			3,287			3,829			4,178		5,132			5,743			3,145
	Minority interest in pre-tax loss of subsidiaries that have not included fixed charges			4,625			2,259			—		2,232			5,999			5,551
As adjusted income (loss)			$	65,733		$	(30,467	)	$	164,232	$	68,763		$	302,523		$	336,885
Fixed charges:
	Interest expense		$	14,562		$	34,495		$	24,188	$	23,289		$	28,022		$	6,362
	Capitalized interest			2,713			4,173			5,250		6,136			8,663			5,167
	Amortization of debt issuance costs(1)			1,148			2,638			2,964		3,311			10,205			1,912
	Portion of rents representative of the interest factor			9,233			11,233			11,833		15,233			15,233			7,617
Total fixed charges			$	27,656		$	52,539		$	44,235	$	47,969		$	62,123		$	21,058
Ratio of earnings to fixed charges(2)				2.4x			—			3.7x		1.4x			4.9x			16.0x

(1)

Amortization of debt issuance costs for the year ended December 31, 2004 includes a charge of $5.3 million to write off the unamortized portion of the debt fees associated with our 3% convertible subordinated debentures, which we redeemed in June 2004.

(2)

The ratio of earnings to fixed charges is not presented for the year ended December 31, 2001 because in such year fixed charges exceeded earnings (as set forth above) by $83.0 million primarily due to:

•

$95.6 million of charges for in-process research and development resulting from the acquisitions of Novazyme Pharmaceuticals, Inc. and Wyntek Diagnostics, Inc.; and



•

a loss of $25.0 million related to the sale of our Snowden-Pencer line of surgical instruments.

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Exhibit 12.1

GENZYME CORPORATION AND SUBSIDIARIES Computation of Ratio of Earnings to Fixed Charges (Amounts in Thousands)