Medidata Solutions Schedules Third Quarter Earnings Conference Call for November 8, 2011

FOR IMMEDIATE RELEASE

Medidata Solutions Schedules Third Quarter Earnings
Conference Call for November 8, 2011

NEW YORK, N.Y. – October 25, 2011 – Medidata Solutions (NASDAQ: MDSO), a leading global provider of SaaS-based clinical development solutions, today announced that it will release its third quarter 2011 financial results before the open of the market on Tuesday, November 8, 2011. Tarek Sherif, chief executive officer, and Cory Douglas, chief financial officer, will also hold a conference call at 8:00 a.m. ET for investors and analysts to review these results and discuss the outlook for the fourth quarter and full year 2011.

To participate by telephone, domestic participants may dial 1-877-303-2528 and international participants may dial 1-847-829-0023. Those interested in participating in the conference call should dial in at least 10 minutes prior to the call to register.

Participants can also join the call via a simultaneous live audio webcast, which will be made available on the “Investor” section of Medidata’s website, http://investor.mdsol.com.

A replay of the conference call can be accessed through Tuesday, November 22, 2011, by dialing 1-855-859-2056 domestically or 1-404-537-3406 internationally, with the passcode 21139769. An archive of the call will also be hosted on the “Investor” section of Medidata’s website, http://investor.mdsol.com, for a limited period of time.

About Medidata Solutions Worldwide
Medidata Solutions is a leading global provider of SaaS clinical development solutions that enhance the efficiency of customers’ clinical trials. Medidata’s advanced solutions lower the total cost of clinical development by optimizing clinical trials from concept to conclusion: from study and protocol design, trial planning and budgeting, site negotiation, clinical portal, trial management, randomization and trial supply management, clinical data capture and management, safety events capture, medical coding to business analytics. Our diverse life science customer base spans biopharmaceutical companies, medical device and diagnostic companies, academic and government institutions, CROs and other research organizations, and includes more than 20 of the top 25 global pharmaceutical companies as well as organizations of all sizes developing life-enhancing medical treatments and diagnostics.

Investor Contact:
Hulus Alpay
Medidata Solutions
212.419.1025
halpay@mdsol.com

Media Contact:
Susan McCarron
Lois Paul & Partners
781.782.5767
Susan_McCarron@lpp.com