Exhibit 23

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We hereby consent to the incorporation by reference in the Registration Statements on Form S-3 (No. 333-146356) and on Form S-8 (Nos. 33-21087, 33-21088, 33-51235, 33-53463, 33-64273, 33-64665, 333-91769, 333-30526, 333-31762, 333-53246, 333-56696, 333-72206, 333-65796, 333-101519, 333-109296, 333-117737, 333-117738, 333-139561 and 333-139562) of Merck & Co., Inc. of our report dated February 26, 2009, except with respect to our opinion on the consolidated financial statements insofar as it relates to the change in accounting for noncontrolling interests, described in Note 2, as to which the date is May 15, 2009, relating to the financial statements and the effectiveness of internal control over financial reporting, which appears in this Form 8-K.

/s/ PricewaterhouseCoopers LLP
Florham Park, NJ
May 15, 2009