Catalyst Rx, the pharmacy benefit management (PBM) subsidiary of Catalyst Health Solutions, Inc. (NASDAQ: CHSI), announced that it will begin contraction negotiations with the State of Mississippi State and School Employees' Health Plan following the State's competitive bid process. Upon successful completion of negotiations, the new contract will be effective January 1, 2011, and will cover approximately 190,000 plan participants.

?Catalyst Rx has enjoyed a strong collaboration with the State of Mississippi over the past four years, and we are grateful for the confidence they've shown in us,? David T. Blair, Chief Executive Officer of Catalyst Health Solutions. ?Our primary goal is to continue delivering transparent and locally-focused solutions to the State, and we thank them for the opportunity to do so.?

Catalyst Rx maintains a local Center of Excellence for State of Mississippi State and School Employees' Health Plan. This service model allows Catalyst Rx to assist the State in managing drug trends through direct patient and prescriber interventions for the greatest care- and cost-effective results.

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 6 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, 2009 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.

Catalyst Health Solutions, Inc.
Hai Tran, Chief Financial Officer
301-548-2900
htran@chsi.com