Exhibit 99.1

Contact:

Ed Stiften, Chief Financial Officer

David Myers, Vice President Investor Relations

(314) 702-7173

investor.relations@express-scripts.com

Express Scripts Declares 2-For-1 Stock Split

ST. LOUIS, May 25, 2005—Express Scripts, Inc. (NASD: ESRX) today announced that its Board of Directors has approved a two-for-one stock split to be effected in the form of a stock dividend. The stock split is for shareholders of record as of June 10, 2005, and will be effective on or about June 24, 2005.

“The stock split reflects the successful execution of our business model, which is built around the alignment of interests with our clients and members,” stated George Paz, president and chief executive officer. “The increased utilization of generics and home delivery services, including specialty pharmacy, translates into lower costs for our clients and improved profitability for Express Scripts.”

Express Scripts, Inc. is one of the largest PBM companies in North America providing PBM services to over 50 million members through facilities in thirteen states and Canada. Express Scripts serves thousands of client groups, including managed care organizations, insurance carriers, third-party administrators, government-sponsored benefit plans, employers, and union-sponsored benefit plans.

Express Scripts provides integrated PBM services, including network pharmacy claims processing, mail pharmacy services, benefit design consultation, drug utilization review, formulary management, disease management, and medical and drug data analysis services. The Company also provides distribution services for specialty pharmaceuticals. Express Scripts is headquartered in St. Louis, Missouri. More information can be found at http://www.express-scripts.com,which includes expanded investor information and resources.

SAFE HARBOR STATEMENT

This press release contains forward-looking statements, including, but not limited to, statements related to the Company’s plans, objectives, expectations (financial and otherwise) or intentions. Actual results may differ significantly from those projected or suggested in any forward-looking statements. Factors that may impact these forward-looking statements include but are not limited to:

• costs of andadverse results in litigation, including a number of pending class action cases that challenge certain of our business practices

• risks arising from investigations of certain PBM practices and pharmaceutical pricing, marketing and distribution practices currently being conducted by the U.S. Attorney offices in Philadelphia and Boston, and by other regulatory agencies including the Department of Labor, and various state attorneys general

• risks anduncertainties regarding the implementation and the ultimate terms of the Medicare Part D prescription drug benefit, including financial risks to us if we participate in the program on a risk-bearing basis and risks of client or member losses to other providers under Medicare Part D

• risks associated with our acquisitions (including our acquisition of CuraScript), which include integration risks and costs, risks of client retention and repricing of client contracts, and risks associated with the operations of acquired businesses

• risks associated with our ability to maintain growth rates, or to control operating or capital costs

• continued pressure on margins resulting from client demands for lower prices, enhanced service offerings and/or higher service levels, and the possible termination of, or unfavorable modification to, contracts with key clients or providers

• competition in the PBM industry, and our ability to consummate contract negotiations with prospective clients, as well as competition from new competitors offering services that may in whole or in part replace services that we now provide to our customers

• adverse results in regulatory matters, the adoption of new legislation or regulations (including increased costs associated with compliance with new laws and regulations), more aggressive enforcement of existing legislation or regulations, or a change in the interpretation of existing legislation or regulations

• increased compliance risks relating to our contracts with the DoD TRICARE Plan and various state governments and agencies

• the possible loss, or adverse modification of the terms, of relationships with pharmaceutical manufacturers, or changes in pricing, discount or other practices of pharmaceutical manufacturers

• risks associated with the possible loss, or adverse modification of the terms of, contracts with pharmacies in our retail pharmacy network

• risks associated with the use and protection of the intellectual property we use in our business

• risks associated with our leverage and debt service obligations, including the effect of certain covenants in our borrowing agreements

• risks associated with our ability to continue to develop new products, services and delivery channels

• general developments in the health care industry, including the impact of increases in health care costs, changes in drug utilization and cost patterns and introductions of new drugs

• increase in credit risk relative to our clients due to adverse economic trends

• risks associated with changes in average wholesale prices, which could reduce prices and margins

• risks associated with our inability to attract and retain qualified personnel

• other risks described from time to time in our filings with the SEC

 We do not undertake any obligation to release publicly any revisions to such forward-looking statements to reflect events or circumstances after the date hereof or to reflect the occurrence of unanticipated events.