Merck Prices $ 6.5 Billion Debt Offering

Merck & Co., Inc.Media Contact:Steven Cragle, 908-423-3461Investor Contact:Carol Ferguson, 908-423-5185

Merck & Co., Inc. priced today a $6.5 billion public offering of senior unsecured notes. The notes include:

$1,000 million of 0.70% notes due May 2016$500 million of floating rate notes due May 2016$1,000 million of 1.30% notes due May 2018$1,000 million of floating rate notes due May 2018$1,750 million of 2.80% notes due May 2023$1,250 million of 4.15% notes due May 2043

Proceeds from the notes will be used to repurchase our common stock and any remaining proceeds will be used for general corporate purposes, including without limitation the repayment of outstanding commercial paper borrowings and upcoming debt maturities. The offering is expected to close on May 20, 2013, subject to customary closing conditions. BNP Paribas Securities Corp., Deutsche Bank Securities Inc., J. P. Morgan Securities LLC and Morgan Stanley & Co. LLC are acting as active joint book-running managers for the offering.

This release does not constitute an offer to sell or a solicitation of an offer to buy the securities described herein, nor shall there be any sale of these securities in any state or jurisdiction in which such an offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such jurisdiction. The offering may be made only by means of a prospectus supplement and accompanying base prospectus. When available, copies of the prospectus supplement and accompanying base prospectus related to the offering may be obtained from BNP Paribas Securities Corp. toll-free at 1-800-854-5674, Deutsche Bank Securities Inc. toll-free at 1-800-503-4611, J.P. Morgan Securities LLC collect at 1-212-834-4533 or Morgan Stanley & Co. LLC toll-free at 1-866-718-1649.

Today's Merck is a global healthcare leader working to help the world be well. Merck is known as MSD outside the United States and Canada. Through our prescription medicines, vaccines, biologic therapies, and consumer care and animal health products, we work with customers and operate in more than 140 countries to deliver innovative health solutions. We also demonstrate our commitment to increasing access to healthcare through far-reaching policies, programs and partnerships.

This news release includes “forward-looking statements” within the meaning of the safe harbor provisions of the United States Private Securities Litigation Reform Act of 1995. These statements are based upon the current beliefs and expectations of Merck’s management and are subject to significant risks and uncertainties. If underlying assumptions prove inaccurate or risks or uncertainties materialize, actual results may differ materially from those set forth in the forward-looking statements.

Risks and uncertainties include but are not limited to, general industry conditions and competition; general economic factors, including interest rate and currency exchange rate fluctuations; the impact of pharmaceutical industry regulation and health care legislation in the United States and internationally; global trends toward health care cost containment; technological advances, new products and patents attained by competitors; challenges inherent in new product development, including obtaining regulatory approval; Merck’s ability to accurately predict future market conditions; manufacturing difficulties or delays; financial instability of international economies and sovereign risk; dependence on the effectiveness of Merck’s patents and other protections for innovative products; and the exposure to litigation, including patent litigation, and/or regulatory actions.

Merck undertakes no obligation to publicly update any forward-looking statement, whether as a result of new information, future events or otherwise. Additional factors that could cause results to differ materially from those described in the forward-looking statements can be found in Merck’s 2012 Annual Report on Form 10-K and the company’s other filings with the Securities and Exchange Commission (SEC) available at the SEC’s Internet site ().