Idenix Pharmaceuticals to Present at Three Upcoming Healthcare Conferences

Idenix Pharmaceuticals, Inc. (Nasdaq:IDIX), announced today that Idenix management will host a fireside chat at the Deutsche Bank Securities 39th Annual Health Care Conference on Wednesday, May 7, 2014 at 3:30 p.m. ET at the InterContinental in Boston, MA. Idenix management will also present a corporate overview at the Bank of America Merrill Lynch 2014 Health Care Conference on Tuesday, May 13, 2014 at 8:00 a.m. PT at the Encore at the Wynn in Las Vegas, NV, and at the 2014 UBS Global Healthcare Conference on Monday, May 19, 2014 at 8:00 a.m. ET at the Sheraton New York Hotel in New York, NY.

The live and archived webcasts of the company presentations can be accessed under "Events and Presentations" in the Idenix Investor Center at www.idenix.com. Please log in approximately 5-10 minutes before each event to ensure a timely connection. The archived replay will be available on the Idenix website for two weeks following the conferences.

ABOUT IDENIX

Idenix Pharmaceuticals, Inc. is a biopharmaceutical Company engaged in the discovery and development of drugs for the treatment of human viral diseases. Idenix is headquartered in Cambridge, Massachusetts (USA). Its clinical development operations and drug discovery operations are conducted in Cambridge and in the Company's European laboratories in Montpellier, France. Idenix's current focus is on the treatment of patients with hepatitis C infection.

For further information about Idenix, please refer to www.idenix.com.

CONTACT: Idenix Pharmaceuticals Contact:
         Teri Dahlman [phone]