Medidata Solutions Schedules First Quarter Earnings Conference Call for May 10, 2011

FOR IMMEDIATE RELEASE

Medidata Solutions Schedules First Quarter
Earnings Conference Call for May 10, 2011

NEW YORK, N.Y. – April 26, 2011 – Medidata Solutions (NASDAQ: MDSO), a leading global provider of SaaS-based clinical development solutions, today announced that it will release its first quarter 2011 financial results following the close of the market on Tuesday, May 10, 2011. Tarek Sherif, chief executive officer, and Bruce Dalziel, chief financial officer and executive vice president, compliance, will also hold a conference call at 5:00 p.m. ET for investors and analysts to review these results and discuss the outlook for the second 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, May 24, 2011, by dialing 1-800-642-1687 domestically or 1-706-645-9291 internationally, with the passcode 62194054. 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 protocol development (Medidata Designer®), trial planning and management (Medidata Grants Manager®, Medidata CRO Contractor®), clinical portal (iMedidata™), randomization and trial supply management (Medidata Balance™), monitoring (Medidata Rave Monitor, Medidata Rave Targeted SDV), safety events capture (Medidata Rave Safety Gateway), clinical data capture and management (Medidata Rave®) to advanced reporting and analytics (Medidata Insights™). 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