IDIX (MM)

Idenix Pharmaceuticals, Inc. (Nasdaq:IDIX) announced today that Idenix management will present a corporate overview at the UBS Global Life Sciences Conference on Thursday, September 20, 2012 at 11:00 a.m. ET at the Grand Hyatt, New York City.

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

About Idenix

Idenix Pharmaceuticals, Inc., headquartered in Cambridge, Massachusetts, is a biopharmaceutical company engaged in the discovery and development of drugs for the treatment of human viral diseases. Idenix's current focus is on the treatment of patients with hepatitis C infection. For further information about Idenix, please refer to http://www.idenix.com.

CONTACT: Idenix Pharmaceuticals Contact:
         Kelly Barry (617) 995-9033 (media)
         Daniella Beckman (617) 995-4471 (investors)