Lance Armstrong was stripped of his record seven Tour de France titles late Thursday after he refused to fight allegations that he used performance-enhancing drugs.

Mr. Armstrong notified the U.S. Anti-Doping Agency that he wouldn't fight the charges the agency brought against him in June, a move that, according to USADA, immediately strips him of all of his athletic titles going back to Aug. 1, 1998, roughly a year before his first Tour de France victory. USADA said Mr. Armstrong is also banned immediately from competing...