Medidata Solutions Files Registration Statement for Public Offering of Common Stock

Medidata Solutions, Inc. (NASDAQ: MDSO), a leading global provider of hosted clinical development solutions, today announced that it filed a registration statement with the Securities and Exchange Commission for a proposed public offering of 4.5 million shares of common stock of the company. The shares are being offered by certain stockholders of the company, including funds affiliated with Insight Venture Partners. Medidata Solutions will not receive any of the proceeds from the intended offering. To the extent that the underwriters sell more than 4.5 million shares of common stock, the selling stockholders intend to grant the underwriters an option for a period of 30 days to purchase up to 675,000 additional shares of common stock.

Citigroup Global Markets, Inc. and Credit Suisse Securities (USA) LLC are acting as joint bookrunning managers for the proposed offering. Jefferies & Company, Inc. and Needham & Company, LLC are acting as co-managers.

When available, a copy of the prospectus may be obtained directly from:

Citigroup Global Markets, Inc:

Brooklyn Army Terminal

140 58th Street, 8th Floor

Brooklyn, N.Y. 11220

Telephone: (718) 765-6732

Or

Credit Suisse Securities (USA) LLC

Prospectus Department

One Madison Avenue

New York, N.Y. 10010

Telephone: (800) 221-1037

A registration statement relating to these securities has been filed with the Securities and Exchange Commission, but has not yet become effective. These securities may not be sold nor may offers to buy be accepted prior to the time the registration statement becomes effective. This press release does not constitute an offer to sell or a solicitation of an offer to buy the securities in this offering, nor shall there be any sale, offer or solicitation of these securities in any state or jurisdiction in which such sale, offer or solicitation would be unlawful.

About Medidata Solutions Worldwide

Medidata Solutions ( www.mdsol.com) is a leading global provider of hosted clinical development solutions that enhance the efficiency of customers’ clinical development processes and optimize their research and development investments. Medidata products and services allow customers to achieve clinical results more efficiently and effectively by streamlining the design, planning and management of key aspects of the clinical development process, including protocol development (Medidata Designer ^®), investigator benchmarking and budgeting (Medidata Grants Manager™), contract research organization (CRO) benchmarking and budgeting (Medidata CRO Contractor™), and the capture, management, analysis and reporting of clinical trial data (Medidata Rave ^®). Medidata’s diverse customer base spans pharmaceutical, biotechnology and medical device companies, academic institutions, CROs and other research organizations, and includes more than 20 of the top 25 global pharmaceutical companies.