Exhibit 23.1

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We hereby consent to the incorporation by reference in the Registration Statements on Form S-3 (Nos. 333-138586, 333-131233, 333-129905 and 333-140076) and Registration Statements on Form S-8 (Nos. 333-127450, 333-116151 333-148114 and 333-157633) of Alnylam Pharmaceuticals, Inc. of our report dated February 26, 2010 relating to the financial statements and the effectiveness of internal control over financial reporting, which appears in this Form 10-K.

/s/ PricewaterhouseCoopers LLP

Boston, Massachusetts
February 26, 2010