Lance Armstrong has been banned from cycling for life and stripped of his seven Tour de France titles, after the International Cycling Union accepted the findings of the US Anti-Doping Agency.
The decision was announced at a UCI news conference.
UCI President Pat McQuaid said Armstrong "has no place in cycling", but that the sport does have a future.
On 10 October, the USADA published a report into Armstrong, which alleged the now retired US rider had been involved in the "most sophisticated, professionalised and successful doping programme sport has ever seen".
Armstrong, 41, had previously elected not to contest USADA charges, prompting it to propose his punishment pending confirmation from cycling's world governing body.
Former Armstrong team mates at his US Postal and Discovery Channel outfits, where he won seven straight Tour titles from 1999 to 2005, testified against him and were given reduced bans by the American authorities.
Armstrong was once widely accepted as one of the greatest cyclists of all time, after he fought back from cancer to dominate the sport.
He has always denied doping and says he has never failed a doping test.
He said he had stopped contesting the charges after years of probes and rumours because "there comes a point in every man's life when he has to say, 'Enough is enough'."
Mr McQuaid, whose organisation has long battled a major doping problem throughout the sport, added: "This is not the first time cycling has reached a crossroads and has had to start anew."
He said he would not be resigning.