Catalyst Health Solutions Makes Fortune 100 Fastest-Growing Companies List for Second Consecutive Year.

ROCKVILLE, Md. -- Catalyst Health Solutions, Inc. (NASDAQ:CHSI) announced today that it was named to the Fortune 100 Fastest-Growing Companies list, making its second consecutive appearance on the annual ranking and third within the past five years. Catalyst ranked Number 14 on the list of fast-growing health care companies and Number 93 overall among all industries. This year, Fortune made both foreign and domestic companies eligible for the list if they are traded on a major U.S. stock exchange. In previous years, only domestic companies were eligible.

"Catalyst is proud to have made the Fortune 100 Fastest-Growing Companies list again," said David T. Blair, Chief Executive Officer of Catalyst Health Solutions, Inc. "To be one of the global growth leaders, despite the tough economic climate, is a testament to our employees' dedication and our proven approach to effectively managing pharmacy costs."

According to Fortune, the 100 Fastest-Growing Companies list was determined as such: To qualify, a company - domestic or foreign - must be trading on a major U.S. stock exchange; file quarterly reports to the SEC; have a minimum market capitalization of $250 million on June 30, 2009; have a stock price of at least $5 on June 30, 2009; have been trading continuously since June 30, 2006; have revenue and net income for the four quarters ended on or before April 30, 2009, of at least $50 million and $10 million, respectively; and have posted a compound annual growth in revenue and earnings per share of at least 20% annually over the three years ended April 30, 2009. All companies that meet these criteria are ranked by their revenue growth rate, their EPS growth rate; and their three-year annualized total return to investors for the period ended June 30, 2009. The overall rank is based on the sum of the three ranks.

The issue of Fortune magazine featuring the 100 Fastest-Growing Companies list is on newsstands now and available online at www.fortune.com.

About Catalyst Health Solutions, Inc. (www.chsi.com)

Catalyst Health Solutions, Inc. is built on strong, innovative principles in the management of prescription drug benefits and provides an unbiased, client-centered philosophy resulting in industry-leading client retention rates. The Company's subsidiaries include Catalyst Rx, a full-service pharmacy benefit manager serving more than six million lives in the United States and Puerto Rico; HospiScript Services, LLC, one of the largest providers of pharmacy benefit management services to the hospice industry; and Immediate Pharmaceutical Services, Inc., a fully-integrated prescription mail service facility in Avon Lake, Ohio. The Company's clients include self-insured employers including state and local governments, managed care organizations, unions, hospices, third-party administrators and individuals.

This press release may contain "forward-looking statements" as defined in the Private Securities Litigation Reform Act of 1995. These statements involve a number of risks and uncertainties that might materially affect our results, particularly those risks referred to in our Annual Report on Form 10-K for the year ended December 31, 2008 under "Item 1A. Risk Factors." Readers are urged to carefully review and consider the various disclosures made in our Annual Report on Form 10-K and our other filings with the Securities and Exchange Commission that attempt to advise interested parties of the risks and uncertainties that may affect our business. Catalyst Health Solutions, Inc. does not undertake any obligation to update forward-looking statements, whether as a result of new information, future events, or other developments.