The US Anti-Doping Agency has filed formal doping charges against Lance Armstrong that, if proven, would strip him of his seven Tour de France titles.
A three-member review panel evaluated evidence gathered by USADA and a reply from Armstrong before unanimously voting to turn the allegations revealed on June 13 into formal charges.
The next step in the process will be a hearing before an arbitration panel.
Their verdict could be appealed and the matter could be pushed to the Court of Arbitration for Sport for a final resolution.
USADA claims it has witnesses to the fact that Armstrong and five former cycling team associates -- including Italian doctor Michele Ferrari and cycling team manager Johan Bruyneel -- engaged in a doping conspiracy from 1998-2011.
Armstrong, who won the Tour de France from 1999-2005 and used his fame to fuel his charitable work for anti-cancer causes, has never tested positive and the 40-year-old US cycling legend has steadfastly denied any wrongdoing.
Last week, in his 18-page reply to USADA's allegations, Armstrong asked the review panel to dismiss the charges, saying the anti-doping group had not offered sufficient proof.
The review panel instead dismissed his position.
Armstrong says the credibility of USADA's case has been undermined by the fact that two key witnesses, Floyd Landis and Tyler Hamilton, are confessed dope cheats themselves.
USADA has said previously that at least 10 former Armstrong teammates and associates would testify against him, but vowed to keep the names confidential.
Armstrong called the allegations against him "baseless" and said the case only recycles "discredited" allegations from the past.
"I have never doped, and, unlike many of my accusers, I have competed as an endurance athlete for 25 years with no spike in performance, passed more than 500 drug tests and never failed one," Armstrong said in a statement when the allegations were made.
"That USADA ignores this fundamental distinction and charges me instead of the admitted dopers says far more about USADA, its lack of fairness and this vendetta than it does about my guilt or innocence."