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UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

FORM 10-Q/A
Amendment No. 1

(Mark One)
ý	QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
For the quarterly period ended June 30, 2010
Or
o	TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
For the transition period from                        to

Commission File No. 0-14680

GENZYME CORPORATION
(Exact name of registrant as specified in its charter)

Massachusetts (State or other jurisdiction of incorporation or organization)	06-1047163 (I.R.S. Employer Identification No.)
500 Kendall Street Cambridge, Massachusetts (Address of principal executive offices)	02142 (Zip Code)
(617) 252-7500 (Registrant's telephone number, including area code)

        Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ý    No o

        Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files). Yes ý    No o

        Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of "large accelerated filer," "accelerated filer" and "smaller reporting company" in Rule 12b-2 of the Exchange Act.

Large accelerated filer ý Accelerated filer o Non-accelerated filer o
(Do not check if a smaller reporting company) Smaller reporting company o

        Indicate by check mark whether the registrant is a shell company (as defined by Rule 12b-2 of the Exchange Act). Yes o    No ý

        Number of shares of Genzyme Stock outstanding as of July 31, 2010: 254,839,847

EXPLANATORY NOTE

        The sole purpose of this amendment to Genzyme Corporation's quarterly report on Form 10-Q for the period ended June 30, 2010, filed with the Securities Exchange Commission on August 9, 2010, is to furnish the interactive data files set forth in Exhibit 101 in accordance with Rule 405 of Regulation S-T.

        No other changes have been made to the Form 10-Q. This amendment speaks as of the original filing date of the Form 10-Q, does not reflect events that may have occurred subsequent to the original filing date, and does not modify or update in any way disclosures made in the Form 10-Q.

ITEM 6.    EXHIBITS

(a)

Exhibits

        See the Exhibit Index following the signature page to this Form 10-Q/A.

SIGNATURES

        Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

	GENZYME CORPORATION
Dated: September 7, 2010	By:	/s/ MICHAEL S. WYZGA Michael S. Wyzga Executive Vice President, Finance, Chief Financial Officer

EXHIBIT INDEX

EXHIBIT NO.		DESCRIPTION
	†**2.1	License and Asset Purchase Agreement dated as of March 30, 2009 and related Letter Agreements between Genzyme Corporation and Bayer Schering Pharma AG, and License Agreement dated as of May 29, 2009 between Genzyme Corporation and Alcafleu Management GmbH & Co. KG.
	*3.1	Restated Articles of Organization of Genzyme Corporation, as amended. Filed as Exhibit 3.1 to Genzyme's Form 8-K filed on June 22, 2010.
	*3.2	By-laws of Genzyme Corporation, as amended. Filed as Exhibit 3.2 to Genzyme's Form 8-K filed June 22, 2010.
	*4.1	Indenture dated as of June 17, 2010 by and between Genzyme Corporation and The Bank on New York Mellon Trust Company, N.A., as Trustee. Filed as Exhibit 4.1(a) to Genzyme's Form 8-K filed on June 17, 2010.
	*4.1.1	First Supplemental Indenture dated as of June 17, 2010 by and among Genzyme Corporation, the Subsidiary Guarantor(s) party thereto from time to time and The Bank of New York Mellon Trust Company, N.A., as Trustee (including forms of 3.625% Senior Note due 2015 and 5.000% Senior Note due 2010). Filed as Exhibit 4.1(b) to Genzyme's Form 8-K filed on June 17, 2010.
	†**10.1	First Amendment to Lease dated May 21, 2010, by and between FC 64 Sidney, Inc. and Genzyme Corporation.
	*10.2	Registration Rights Agreement dated June 17, 2010 by and among Genzyme Corporation, Credit Suisse Securities (USA) LLC, Goldman, Sachs & Co. and Banc of America Securities LLC. Filed as Exhibit 10.1 to Genzyme's Form 8-K filed on June 17, 2010.
	†10.3	Master Confirmation dated June 17, 2010 between Genzyme Corporation and Goldman, Sachs & Co.
	†**10.3.1	Supplemental Confirmation dated June 17, 2010 between Genzyme Corporation and Goldman, Sachs &Co.
	*10.4	Consent Decree dated May 24, 2010 between Genzyme Corporation and the United States Food and Drug Administration. Filed as Exhibit 99.1 to Genzyme's Form 8-K filed on May 24, 2010.
	*10.5	Amended and Restated agreement dated April 14, 2010 between Genzyme, Relational Investors LLC, Ralph V. Whitworth and the other parties identified therein. Filed as Exhibit 99.1 to Genzyme's Form 8-K filed on April 15, 2010.
	*10.6	Agreement dated June 9, 2010 by and among Genzyme Corporation, Icahn Partners LP, Icahn Partners Master Fund LP, Icahn Partners Master Fund II L.P., Icahn Partners Master Fund III L.P. and High River Limited Partnership. Filed as Exhibit 99.1 to Genzyme's Form 8-K filed on June 30, 2010.
	†***10.7	2004 Equity Incentive Plan, as amended.
	†***10.8	2007 Director Equity Plan, as amended.
	†**10.9	Master Supply Agreement dated as of June 30, 2010 among Genzyme Corporation, Genzyme Ireland Limited and Hospira Worldwide, Inc.
	†**10.10	License Agreement dated as of January 1, 1995 and First Amendment thereto, dated as of October 7, 2003, between Genzyme Corporation and Mount Sinai School of Medicine of the City University of New York.

EXHIBIT NO.		DESCRIPTION
	†31.1	Certification of the Chief Executive Officer pursuant to section 302 of the Sarbanes-Oxley Act of 2002.
	†31.2	Certification of the Chief Financial Officer pursuant to section 302 of the Sarbanes-Oxley Act of 2002.
	†32.1	Certification of the Chief Executive Officer pursuant to section 906 of the Sarbanes-Oxley Act of 2002.
	†32.2	Certification of the Chief Financial Officer pursuant to section 906 of the Sarbanes-Oxley Act of 2002.
	‡101	The following materials from Genzyme Corporation's Form 10-Q for the quarter ended June 30, 2010, formatted in eXtensible Business Reporting Language (XBRL): (i) Consolidated Statements of Operations, (ii) Consolidated Balance Sheets, (iii) Consolidated Statements of Cash Flows and (iv) Notes to Unaudited, Consolidated Financial Statements. Furnished herewith.

*

Indicates exhibit previously filed with the SEC and incorporated herein by reference. Exhibits filed with Forms 10-Q and 8-K of Genzyme Corporation were filed under Commission File No. 0-14680.

**

Confidential treatment has been requested and/or granted for the deleted portions of the exhibit.

***

Exhibit is a management contract or compensatory plan or arrangement in which our executive officers or directors participate.

†

Filed or furnished with the initial filing of this Form 10-Q filed on August 9, 2010.

‡

Pursuant to Rule 406T of Regulation S-T, the interactive data files included in Exhibit 101 are deemed not filed or part of a registration statement or prospectus for purposes of Sections 11 or 12 of the Securities Act of 1933, as amended, are deemed not filed for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, and otherwise are not subject to liability under those sections.

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EXPLANATORY NOTE

ITEM 6. EXHIBITS

SIGNATURES
EXHIBIT INDEX