Lance Armstrong said he has been through a "difficult couple of weeks" and urged supporters of his cancer-fighting charity to stand behind its mission.
Armstrong gave the welcoming remarks at the 15th anniversary celebration for Livestrong, the charity he founded in 1997.
He stepped down as chairman on Wednesday in an effort to ward off damage caused by doping charges against him.
The event drew 1,700 supporters, cancer survivors and Armstrong friends, and they gave him a standing ovation before he spoke.
Armstrong, who denies using performance enhancing drugs to help him win the Tour de France seven times, did not address doping evidence presented last week by the US Anti-Doping Agency.