Joint Filing Agreement

Exhibit A

Joint Filing Agreement

     The undersigned hereby agree that the statement on Schedule 13G with respect to the Common Stock, $0.50 par value of Carmax, Inc., dated as of February 13, 2003, is, and any amendments thereto (including amendments on Schedule 13D) signed by each of the undersigned shall be, filed on behalf of each of us pursuant to and in accordance with the provisions of Rule 13d-1(k) under the Securities Exchange Act of 1934.

Date: February 13, 2003

		MAVERICK CAPITAL, LTD.
		By:		Maverick Capital Management, LLC
				Its General Partner
				By:		Xxx X. Xxxxxxx III, Manager
						By:		/s/ Xxxx X. XxXxxxxxxx
								Xxxx X. XxXxxxxxxx
								Under Power of Attorney dated
								February 13, 2003
		MAVERICK CAPITAL MANAGEMENT, LLC
		By:		Xxx X. Xxxxxxx III, Manager
				By:		/s/ Xxxx X. XxXxxxxxxx
						Xxxx X. XxXxxxxxxx
						Under Power of Attorney dated
						February 13, 0000
		XXX X. XXXXXXX III
		By:		/s/ Xxxx X. XxXxxxxxxx
				Xxxx X. XxXxxxxxxx
				Under Power of Attorney dated
				February 13, 2003