UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 OR 15(d) of The

Securities Exchange Act of 1934

Date of Report (Date of earliest event reported) June 1, 2011

CATALYST HEALTH SOLUTIONS, INC.

(Exact name of registrant as specified in its charter)

800 King Farm Boulevard

Rockville, Maryland 20850

(Address of principal executive offices) (Zip Code)

Registrant’s telephone number, including area code (301) 548-2900

Not Applicable

(Former name or former address, if changed since last report.)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

On June 1, 2011, Hai Tran stepped down from his position as Chief Financial Officer and Treasurer of Catalyst Health Solutions, Inc. (the “Company”), effective July 15, 2011.

On June 1, 2011, the Company’s Board of Directors appointed Deirdre Kramer, the Company’s Corporate Controller and Senior Vice President, Finance, to serve as interim Chief Financial Officer until a permanent replacement for Mr. Tran is selected. Ms. Kramer, age 39, joined the Company in 2005 and has more than 15 years experience in the health care and pharmacy benefit management industries. In her current role at the Company, she is responsible for the overall management of corporate accounting as well as financial planning and analysis. Prior to joining the Company, Ms. Kramer served as Director of Finance and Accounting at Eckerd Health Services, the former pharmacy benefit management subsidiary of Eckerd Corp.

The annual meeting of the shareholders of the Company was held on June 1, 2011. The Company previously filed with the Securities and Exchange Commission the proxy statement and related materials pertaining to this meeting, which describe in detail each of the four proposals submitted to shareholders at the meeting. The final results for the votes regarding each proposal are set forth below.

Proposal 1: Election of Directors

Elected the three nominees for the Board of Directors to the class of directors with a term expiring at the annual meeting of shareholders in 2014 and until their successors are elected and qualified.

Proposal 2: Ratification of the Appointment of PricewaterhouseCoopers LLP as the Company’s Independent Registered Public Accounting Firm

Ratified the appointment of PricewaterhouseCoopers LLP as the Company’s independent registered public accounting firm for the year ended December 31, 2011.

Proposal 3: Approval of the Compensation of our Named Executive Officers

Approved, on an advisory basis (non-binding), the compensation of the Company’s named executive officers as described in the Compensation Discussion and Analysis and the accompanying tables in our 2011 proxy statement.

Proposal 4: Frequency of Holding Future Advisory Votes on the Compensation of our Named Executive Officers

Approved, on an advisory basis (non-binding), a frequency period of every year (an annual vote) for future votes on the compensation of our named executive officers.

The option to hold future advisory votes on the compensation of our named executive officers on an annual basis received a majority of the votes cast at the annual meeting. Based on these results, the Company’s Board of Directors has determined to hold an annual advisory vote on executive compensation.

On June 3, 2011, the Company issued a press release. A copy of the press release is attached to this Current Report on Form 8-K as Exhibit 99.1 and incorporated herein by reference.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.