IDIX (MM)

Idenix Pharmaceuticals, Inc. (Nasdaq:IDIX) announced today that the Company's third quarter 2013 financial results will be released after close of market on Wednesday, October 30, 2013.

Idenix management will host a conference call at 4:30 p.m. ET on Wednesday, October 30, 2013, to discuss the Company's financial results for the third quarter of 2013 and provide an update on the Company's development programs.

To access the call, please dial (877) 640-9809 (U.S./Canada) or (914) 495-8528 (International) and enter passcode 90503423.  A live webcast will be available via the Investor section of the Idenix website at www.idenix.com under "Events & Presentations".  The archived webcast will be available for two weeks following the call on the Idenix website.

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 www.idenix.com.

CONTACT: Idenix Pharmaceuticals Contact:
         Teri Dahlman
         (617) 995-9807