Amendment to Employment Agreement by and between Catalyst Health Solutions, Inc. and Richard A. Bates, effective June 22, 2010

Exhibit 10.1

Amendment to Employment Agreement by and between

Catalyst Health Solutions, Inc. and Richard A. Bates, effective June 22, 2010

Reference is made to the Employment Agreement between Catalyst Health Solutions, Inc. (the “Company”) and Richard A. Bates (the “Executive”) dated August 3, 2009 (the “Employment Agreement”).

Whereas, the Company and Executive previously entered into the Employment Agreement, pursuant to which Executive served as Executive Vice President of the Company;

Whereas, the Company and Executive desire that Executive shall assume the title and duties of President and Chief Operating Officer of the Company and no longer serve as Executive Vice President the of the Company, effective as of the Amendment Date (as defined below);

Now, therefore, in consideration of the premises and mutual covenants herein and for other good and valuable consideration, the parties hereby agree to this amendment to the Employment Agreement (the “Amendment”) as follows, effective as of the Amendment Date:

In Section 2.1 and 8.1.B (iv), all references to “Executive Vice President” shall be changed to “President and Chief Operating Officer.”

This Amendment shall have no effect until approved by the Company Board of Directors.

Except as modified above, all other terms and conditions of the Employment Agreement shall remain in full force and effect as originally stated, this Amendment is hereby made a part of the Employment Agreement and neither party shall invoke any rights to terminate the Employment Agreement for any matter related to the Amendment.

IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be executed as of the date shown below (the “Amendment Date”).

Board Approval Date: June 22, 2010

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