Exhibit 99.1

Medidata Solutions Reports Third Quarter 2011 Results

Record year to date GAAP and Non-GAAP operating income* increased 62% and 36%,
to $21.8 and $34.1 million, respectively, year over year

Quarterly GAAP and Non-GAAP operating income increased 25% and 18%,
to $7.6 and $11.9 million, respectively, year over year

Cash flow from operations increased 256% to $26.3 million
Customers increased 14%, or 33, to 261

Reiterates full year and provides fourth quarter 2011 guidance

NEW YORK--(BUSINESS WIRE)--November 8, 2011--Medidata Solutions (NASDAQ: MDSO), a leading global provider of SaaS-based clinical technology solutions that enhance the efficiency of clinical development, today announced its financial results for the third quarter 2011, as well as provided financial guidance for the fourth quarter and full year 2011.

“Medidata’s strong Q3 and record year to date results reflect the unique business value that our SaaS-based product portfolio brings to the clinical development process,” said Tarek Sherif, Medidata's chief executive officer. “Our role as a leading supplier of critical infrastructure and business analytics to the global life sciences and CRO sectors is driving increased revenues, profits and market share. We are operating in healthy and vibrant markets, with significant opportunities for growth, and are very well positioned for continued success in the coming year.”

Third Quarter Highlights

• Revenues increased to $46.3 million, up 13% year on year.
• Gross margins were 71%, up 3% year on year, and above the company’s previously stated long-term target range.
• GAAP and Non-GAAP operating income increased 25% and 18% year on year, to $7.6 and $11.9 million, respectively.
• Year to date GAAP and Non-GAAP operating income increased 62% and 36%, to a record $21.8 and $34.1 million, respectively.
• Year to date GAAP and Non-GAAP operating margins increased to a record 16% and 25%, respectively.
• Cash flow from operations increased 256% year to date to a record $26.3 million.
• Medidata added 33 new customers, including 18 from Clinical Force, for a quarter-end total of 261.
• Customers continued to contract for additional products from Medidata’s expanded portfolio, with over 10% of Medidata's customer base buying additional products this quarter.
• A global pharmaceutical company and one of Medidata’s top 4 customers extended its multi-year enterprise agreement with Medidata this quarter, continuing its long-time use of Rave, and expanded its use of Medidata's capabilities to include several non-Rave offerings, including Balance, Coder, TSDV and Safety Gateway.
• One of China’s largest CROs, Hangzhou Tigermed Consulting Ltd., became a Medidata Services Partner. Clinical Financial Services (CFS), which offers comprehensive business and financial management services for clinical trials, joined the Medidata Technology Partner program.
• Medidata launched Medidata Coder, an easy-to-use, easy-to-maintain software-as-a-service (SaaS) solution that provides a centralized coding environment designed to reduce coding cycle times.

Sherif added, “The integration of the previously announced acquisition of Clinical Force into our company is progressing well. We are working with existing CTMS customers to ensure a smooth transition and are focused on developing a world class CTMS SaaS offering that will benefit Medidata’s global customers and partners.”

Financial Highlights

Net revenues for the third quarter of 2011 were $46.3 million, an increase of $5.2 million, or 13%, compared with $41.1 million in the third quarter of 2010. The increase in revenues was due to a $1.4 million, or 4%, increase in revenues from application services, and a $3.8 million increase in revenues from professional services.

Gross margins in the third quarter of 2011 were 71%, an increase of approximately 3 percentage points over gross margins of 68% a year ago.

Non-GAAP operating income for the third quarter of 2011 increased 18% to $11.9 million, compared with $10.1 million a year ago. GAAP operating income for the quarter increased 25% to $7.6 million, compared with $6.0 million a year ago.

Non-GAAP net income* for the third quarter of 2011 increased to $10.4 million, or $0.42 per diluted share, compared with $6.9 million, or $0.29 per diluted share, in the third quarter of 2010. AAP net income for the third quarter of 2011 increased to $7.5 million, or $0.31 per diluted share, compared with $4.7 million, or $0.20 per diluted share, in the third quarter of 2010.

Cash flow from operations for the third quarter increased to a record $26.3 million, due to the company’s improving profitability and changes in working capital.

Financial Outlook

For the full year 2011, the company expects revenues to be between $183 and $185 million. Non-GAAP operating income is expected to be between $44.5 and $45.5 million. Based on current estimates, this would equate to GAAP operating income between $27.5 and $28.5 million. Non-GAAP net income is expected to be between $36.5 and $37.5 million. Based on current estimates, this would equate to GAAP net income between $26.5 and $27.5 million.

Total remaining backlog for 2011 was $39 million at the end of the third quarter. Remaining year backlog represents the amount of contractual revenue already booked, which is expected to be recognized during the remainder of the year. The difference between the backlog and balance of revenue guidance for the remainder of the year includes revenue from incremental professional services, as well as additional business from new and existing customers.

For the fourth quarter of 2011, the company expects revenues to be between $46.0 and $47.5 million. The company expects non-GAAP operating income to be between $10.5 and $11.5 million. Based on current estimates this would equate to GAAP operating income of $6.0 and $7.0 million. Non-GAAP net income is expected to be between $8.5 and $9.5 million. Based on current estimates, this would equate to GAAP net income of between $6.0 and $7.0 million.

While changes in the stock price could change the fully diluted share count, the company is assuming 24.5 and 24.7 million fully diluted shares in the fourth quarter and full year, respectively.

“We witnessed solid margin expansion and record cash flow this quarter,” said Cory Douglas, chief financial officer. “The scalability of our growing SaaS-based clinical development platform and the long term leverage in our business model are driving our profitable growth.”

Conference Call

The company plans to host its investor conference call today at 8:00 a.m. Eastern. The investor conference call will be available via live webcast on the “Investor” section of Medidata’s web site at http://investor.mdsol.com. To participate by telephone, domestic participants may dial 877-303-2528 and international participants may dial 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 web site at http://investor.mdsol.com. A replay of the conference call can be accessed until Tuesday, November 22, 2011 by dialing 855-859-2056 domestically or 404-537-3406 internationally, with the passcode 21139769. An archive of the call will also be hosted on the “Investor” section of Medidata’s web site, 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.

Cautionary Statement

Certain statements made in this press release are “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995 that involve significant risks and uncertainties about Medidata Solutions, Inc. (“Medidata”), including but not limited to statements about Medidata’s forecast of financial performance, products and services, business model, strategy and growth opportunities, and competitive position. Such statements are subject to risks and uncertainties that could cause actual performance or results to differ materially from those expressed in these statements. In particular, the risks and uncertainties include, among other things, risks associated with possible fluctuations in our financial and operating results; errors, interruptions or delays in our service or our Web hosting; the financial impact of any future acquisitions; our ability to continue to release, and gain customer acceptance of, new and improved versions of our products; changes in our sales and implementation cycles; competition; our ability to retain and expand our customer base or increase new business from those customers; our ability to hire, retain and motivate our employees and manage our growth; regulatory developments; litigation; and general developments in the economy. For additional disclosure regarding these and other risks faced by the company, see disclosures contained in Medidata's public filings with the Securities and Exchange Commission including, the “Risk Factors” section of Medidata’s Annual Report on Form 10-K for the year ended December 31, 2010. You should consider these factors in evaluating the forward-looking statements included in this press release and not place undue reliance on such statements. The forward-looking statements are made as of the date hereof, and Medidata undertakes no obligation to update such statements as a result of new information.

*Non-GAAP Financial Information

Medidata provides Non-GAAP operating income, net income and net income per share applicable to common stockholders data as additional information for its operating results. These measures are not in accordance with, or an alternative for, generally accepted accounting principles and may be different from Non-GAAP measures used by other companies. Non-GAAP operating income excludes the impact of depreciation, amortization of purchased intangible assets and acquisition-related charges and stock-based compensation expense. Non-GAAP net income excludes the impact of amortization of intangible assets associated with acquisitions and stock-based compensation expense. Management uses these Non-GAAP measures to evaluate its financial results, develop budgets, manage expenditures, and as an important factor in determining variable compensation. In addition, investors frequently have requested information from management regarding depreciation and amortization and non-cash, share-based compensation charges and management believes, based on discussions with investors, that these Non-GAAP measures enhance investor’s ability to assess Medidata’s historical and project future financial performance. While management believes these Non-GAAP financial measures provide useful supplemental information to investors, there are limitations associated with the use of Non-GAAP financial measures. One limitation of Non-GAAP operating income is that it excludes depreciation and amortization, which represents the periodic costs of certain capitalized tangible and intangible assets used in generating revenues in our business. Medidata compensates for these limitations by using these non-GAAP financial measures as supplements to GAAP financial measures and by reviewing the reconciliations of the Non-GAAP financial measures to their most comparable GAAP financial measures. Investors are encouraged to review the reconciliations of these Non-GAAP financial measures to the comparable GAAP results, which are attached to this press release.

The table above presents a reconciliation of GAAP to non-GAAP operating income, net income and net income per share applicable to common stockholders for the three and nine months ended September 30, 2011. Non-GAAP operating income excludes the impact of depreciation, amortization of intangible assets associated with acquisitions and stock-based compensation expense. Non-GAAP net income excludes the impact of amortization of intangible assets associated with acquisitions and stock-based compensation expense.

CONTACT:
Investor Contact:
Medidata Solutions
Hulus Alpay, 212-419-1025
halpay@mdsol.com
or
Media Contact:
Lois Paul & Partners
Susan McCarron, 617-986-5767
susan_mccarron@lpp.com