Lance Armstrong attempted to make a donation of "in excess of £150,000" to the US Anti Doping Agency shortly before his seventh Tour de France title, according to Travis Tygart, the organisation's chief executive.
"I was stunned," Tygart told CBS News. "It was a clear conflict of interest. We had no hesitation in rejecting that offer."
In August, Armstrong was stripped of his titles and banned from cycling after declining to contest doping charges against him.
His first interview since the ban is due to air on Oprey Winfrey's TV network next week.
More top news
A cancer patient has taken legal action against an NHS trust after suffering permanent life-changing injuries following routine surgery.
One of the six survivors of a horror plane crash which killed 71 people has appeared on camera to thank his supporters.
Giraffes could disappear from the planet if current rates of extinction continue, it has been warned.