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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
			Year Ended December 31,
																		June 30, 2004
			1999			2000			2001			2002			2003
Income (loss) before income taxes			$	117,928		$	(7,462	)	$	(118,343	)	$	104,211		$	5,055		$	208,452
Add: equity in loss of equity method investments				42,696			44,965			35,681			16,858			16,743			8,105
Deduct: minority interest				(3,674	)		(4,625	)		(2,259	)		—			(2,232	)		(2,126	)
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			214,431
Add:
	Fixed charges:
		Portion of rents representative of the interest factor		7,533			9,233			11,233			11,833			15,233			7,617
		Amortization of debt issuance costs(1)		1,333			1,148			2,638			2,964			3,311			8,293
		Interest expense		20,438			14,562			34,495			24,188			23,289			19,528
	Amortization of capitalized interest			3,021			3,287			3,829			4,178			5,132			2,872
	Minority interest in pre-tax loss of subsidiaries that have not included fixed charges			3,674			4,625			2,259			—			2,232			2,126
As adjusted income (loss)			$	192,949		$	65,733		$	(30,467	)	$	164,232		$	68,763		$	254,867
Fixed charges:
	Interest expense		$	20,438		$	14,562		$	34,495		$	24,188		$	23,289		$	19,528
	Capitalized interest			1,329			2,713			4,173			5,250			6,136			4,119
	Amortization of debt issuance costs(1)			1,333			1,148			2,638			2,964			3,311			8,293
	Portion of rents representative of the interest factor			7,533			9,233			11,233			11,833			15,233			7,617
Total fixed charges			$	30,633		$	27,656		$	52,539		$	44,235		$	47,969		$	39,557
Ratio of earnings to fixed charges(2)				6.3	x		2.4	x		—			3.7	x		1.4	x		6.4	x

(1)

Amortization of debt issuance costs for the six months ended June 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)