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 (Nos. 33-39349, 33-60322, 33-51785, 33-57421, 333-17045, 333-36383, 333-77569, 333-72546, 333-87034 and 333-118186) and on Form S-8 (Nos. 33-21087, 33-21088, 33-40177, 33-51235, 33-53463, 33-64273, 33-64665, 333-91769, 333-30526, 333-31762, 333-40282, 333-53246, 333-56696, 333-72206, 333-65796, 333-101519, 333-109296, 333-117737 and 333-117738) of Merck & Co., Inc. of our report dated February 22, 2005, relating to the consolidated financial statements, management’s assessment of the effectiveness of internal control over financial reporting and the effectiveness of internal control over financial reporting, which appears in this Current Report on Form 8-K of Merck & Co., Inc. dated February 28, 2005.

/s/ PricewaterhouseCoopers LLP

Florham Park, New Jersey
February 28, 2005