Conference Call to Discuss Q2 2007 Results and the Company's Financial Outlook.

BETHESDA, Md., July 11 /PRNewswire-FirstCall/ -- The following is being issued by CoStar Group, Inc. :

Hosted by Andrew C. Florance, President & Chief Executive Officer and Brian J. Radecki, Chief Financial Officer

   (Logo:  http://www.newscom.com/cgi-bin/prnh/20060510/COSTARLOGO )    PRESS RELEASE:   After the market close on Wednesday, July 25, 2007    CONFERENCE CALL:   Thursday, July 26, 2007   11:00 AM - Noon (ET)    U.S. Dial-In Number:  (800) 329-4405   International Dial-In Number:  (706) 634-0964    Live web broadcast can be found at:   http://www.costar.com/corporate/investor/    CONFERENCE CALL REPLAY:   U.S. Dial-In Number:  (800) 642-1687   International Dial-In Number:  (706) 645-9291   Conference ID:  6859325   

A telephonic replay of the conference call will be available two hours after the live call concludes through midnight on August 3, 2007. The replay will also be available over the Internet at http://www.costar.com/corporate/investor for a period of time following the call.

   Costar Group, Inc.    http://www.costar.com/  

CONTACT: Analysts, Investors, Brian J. Radecki, Chief Financial Officer of Costar Group, Inc., +1-301-664-9132, bradecki@costar.com; Media, Tim Trainor, Corporate Communications of Costar Group, Inc., +1-301-280-7695, ttrainor@costar.com

Web site: http://www.costar.com/