Medidata Solutions Schedules Third Quarter Earnings Conference Call for November 9, 2010

FOR IMMEDIATE RELEASE

Medidata Solutions Schedules Third Quarter Earnings
Conference Call for November 9, 2010

NEW YORK, N.Y. – October 26, 2010 – Medidata Solutions (NASDAQ: MDSO), a leading global provider of SaaS-based clinical development solutions, today announced that it will release its third quarter 2010 financial results following the close of the market on Tuesday, November 9, 2010. Tarek Sherif, chief executive officer, and Bruce Dalziel, chief financial officer, 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 fourth quarter and full year 2010.

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 until Tuesday, November 23, 2010, by dialing 1-800-642-1687 domestically or 1-706-645-9291 internationally, with the passcode 18376284. 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 (www.mdsol.com) is a leading global provider of SaaS-based clinical development solutions that enhance the efficiency of customers’ clinical trials. For over 10 years, Medidata has consistently brought next-generation innovation to the life science industry to lower the total cost of clinical development through informed trial planning and management, optimized clinical processes and platform interoperability. Medidata’s advanced solutions address key functions throughout the clinical development process including protocol development (Medidata Designer®), trial planning and management (Medidata Grants Manager®, Medidata CRO Contractor®), user and learning management (iMedidata™), randomization and trial supply management (Medidata Balance™), monitoring (Medidata Rave Monitor, Medidata Rave Targeted SDV), Serious Adverse Events capture (Medidata Rave Safety Gateway) and clinical data capture, management and reporting (Medidata Rave®). Our diverse 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