The decision effectively destroyed Armstrong's last hope of clearing his name after he was exposed as a drug cheat, triggering a wave of condemnation and legal threats.
A Texas promotions company that paid out millions of dollars in bonuses to Armstrong said it wanted its money back while Sunglasses maker Oakley announced it was ending its sponsorship of the disgraced American.
The World Anti-Doping Agency said it understood the UCI's decision to ban Armstrong while USADA called for a full and independent investigation into professional cycling.
"It is important to remember that while today is a historic day for clean sport, it does not mean clean sport is guaranteed for tomorrow," USADA chief executive Travis Tygart said.
UCI president Pat McQuaid conceded cycling was in crisis but said no-one should feel any sympathy for Armstrong, a cancer survivor whose fairytale rise to the top has been shattered by revelations of his use of performance-enhancing drugs.
"Lance Armstrong has no place in cycling. Lance Armstrong deserves to be forgotten in cycling," McQuaid said.
"I was sickened by what I read in the USADA report."
McQuaid, who was criticised for his and the UCI's handling of the affair, pledged to do more to clean up the tainted sport but said he would not be standing down from his position.
"Cycling has a future. This is not the first time cycling has reached a crossroads or that it has had to begin anew," he said.
"I am sorry we couldn't catch every damn one of them red handed and throw them out of the sport."
McQuaid said the UCI would meet on Friday to discuss whether Armstrong would have to repay any prizemoney he earned or whether his titles would be re-awarded to other cyclists.
Tour de France director Christian Prudhomme had said no other riders should be given the titles because doping was so widespread in the peloton at the time but McQuaid said that was a matter for the UCI to decide.
The International Olympic Committee said it would take its time to digest the news amid suggestions that Armstrong could be stripped of his 2000 Sydney Olympics time trial bronze.
"We will study UCI's response to the USADA report and await to receive their full decision including further potential sanctions against Lance Armstrong as well as regarding any ramifications to his case," an IOC official said.
Dallas-based SCA Promotions said it had paid Armstrong around $12 million in bonuses and attorney fees for his Tour de France wins but the company's lawyer Jeffrey Dorough said he should have to pay back some of the money.
"Mr. Armstrong is no longer the official winner of any Tour de France races, and as a result it is inappropriate and improper for him to retain any bonus payments made by SCA," Dorough said in a statement.
Legal experts said it was unlikely US prosecutors would reopen a criminal investigation into Armstrong which was closed earlier this year and if they did it was even less likely he would end up behind bars.
The Department of Justice in Washington and the US Attorney's in Los Angeles declined to comment but Geoffrey Rapp, a law professor at the University of Toledo's law school, said: "I don't see Armstrong going to jail."
Despite agreeing that Armstrong cheated his way to the top, USADA and UCI continued to trade thinly veiled insults on Monday.
McQuaid said USADA should have handed over its evidence to a neutral investigator and said anti-doping agencies needed to share the blame because their tests failed to catch him.
USADA responded by saying the UCI's banning of Armstrong was not the end of the problem because USADA's investigation showed that doping was rife in professional cycling.
"There are many more details of doping that are hidden, many more doping doctors, and corrupt team directors and the omerta (code of silence) has not yet been fully broken."
On October 10, USADA published a report into Armstrong which alleged the now-retired rider had been involved in the "most sophisticated, professionalised and successful doping program that sport has ever seen".
Armstrong, 41, had previously elected not to contest USADA charges, prompting USADA 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 his seven successive Tour titles from 1999 to 2005, testified against him and themselves and were given reduced bans by the American authorities.
"It wasn't until the intervention of federal agents...they called these riders in and they put down a gun and badge on the table in front of them and said 'you're now facing a grand jury you must tell the truth' that those riders broke down," McQuaid added.
Armstrong, widely accepted as one of the greatest cyclists of all time given he fought back from cancer to dominate the sport, 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'".
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