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Exhibit 12.1

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

			Year Ended December 31,															Nine Months Ended September 30, 2004
			1999			2000			2001			2002			2003
Income (loss) before income taxes			$	117,928		$	(7,462	)	$	(118,343	)	$	104,211		$	5,055		$	348,730
Add: equity in loss of equity method investments				42,696			44,965			35,681			16,858			16,743			12,467
Deduct: minority interest				(3,674	)		(4,625	)		(2,259	)		—			(2,232	)		(3,715	)
Income (loss) before income taxes, equity in loss of equity method investments and minority interest				156,950			32,878			(84,921	)		121,069			19,566			357,482
Add:
	Fixed charges:
		Portion of rents representative of the interest factor		7,533			9,233			11,233			11,833			15,233			11,425
		Amortization of debt issuance costs(1)		1,333			1,148			2,638			2,964			3,311			9,249
		Interest expense		20,438			14,562			34,495			24,188			23,289			24,001
	Amortization of capitalized interest			3,021			3,287			3,829			4,178			5,132			4,308
	Minority interest in pre-tax loss of subsidiaries that have not included fixed charges			3,674			4,625			2,259			—			2,232			3,715
As adjusted income (loss)			$	192,949		$	65,733		$	(30,467	)	$	164,232		$	68,763			410,180
Fixed charges:
	Interest expense		$	20,438		$	14,562		$	34,495		$	24,188		$	23,289		$	24,001
	Capitalized interest			1,329			2,713			4,173			5,250			6,136			6,242
	Amortization of debt issuance costs(1)			1,333			1,148			2,638			2,964			3,311			9,249
	Portion of rents representative of the interest factor			7,533			9,233			11,233			11,833			15,233			11,425
Total fixed charges			$	30,633		$	27,656		$	52,539		$	44,235		$	47,969		$	50,917
Ratio of earnings to fixed charges(2)				6.3	x		2.4	x		—			3.7	x		1.4	x		8.1	x

(1)

Amortization of debt issuance costs for the nine months ended September 30, 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)