Item 5.02. Departure of Directors or Certain Officers; Election of Directors;
Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

(b) On December 3, 2008, Peter Barrett submitted his resignation to the Board of Directors of Momenta Pharmaceuticals, Inc. (the "Company"), effective as of the close of business on December 4, 2008. Mr. Barrett's decision to resign from the Company's Board of Directors is not the result of any disagreement with the Company, known to an executive officer of the Company, on any matter relating to the registrant's operations, policies or practices.

The full text of the Company's press release issued in connection with the announcement is furnished as Exhibit 99.1 to this Current Report on Form 8-K.

Item 9.01. Financial Statements and Exhibits

(d) Exhibits

99.1. Press Release issued by Momenta Pharmaceuticals, Inc. on December 5, 2008.

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