The Court of Arbitration for Sport (Cas) has banned Alberto Contador for two years for doping.
He has been stripped of his 2010 Tour de France victory and, with his suspension running until 5 August, will miss this year's Tour and the Olympics.
Matt SlaterSports news reporter
A reputation in the balance, a wronged rival, political interference, legal wrangling and the honour of thousands of Spanish farmers at stake, so to speak: this tale had it all. Now, 18 months later, we have an answer. Contador had a performance-enhancing drug in his system and cannot explain why. Records will be rewritten, jerseys will change hands, but the debate about the man, cycling and sport's fight against cheats will continue with renewed intensity.
He has maintained that the failed test was a result of eating contaminated meat.
Andy Schleck of Luxembourg, who finished second to Contador in the 2010 Tour de France, is set to be elevated to champion.
Schleck said: "First of all I feel sad for Alberto. I always believed in his innocence. This is just a very sad day for cycling [but] we can finally move on."
Under the rules of the world governing body, Union Cycliste Internationale (UCI), Contador also forfeits all his wins in 2011, which include the Giro d'Italia.
Contador's ban is backdated from 25 January 2011, the date the Spanish Cycling Federation (REFC) initially proposed a one-year ban, which was rejected by Contador.
REFC cleared Contador the following month, but the UCI and World Anti-Doping Agency (Wada) appealed against that decision to Cas, which upheld the appeal after twice postponing the hearing.
Contador is tested on second rest day of Tour de France after traces of clenbuterol are found
Four days later he wins his third Tour de France, beating Andy Schleck into second
Contador reveals positive test and blames contaminated steak
President of Spanish Cycling Federation recommends one-year ban
Contador tells media he will quit if he loses his appeal
Spanish Prime Minister tweets his support for Contador; Spanish Cycling Federation (RFEC) clears him
World governing body UCI and World Anti-Doping Agency appeals RFEC decision to Court of Arbitration for Sport (Cas)
Contador wins Giro d'Italia for the second time
Contador gives evidence at hearing
Cas bans Contador for two years
Since Contador served five months and 19 days of a provisional suspension in 2010-11, his ban will run until 5 August this year rather than 25 January 2013.
The verdict was handed down by a three-man jury consisting of Israeli Efraim Barack, Quentin Byrne-Sutton of Switzerland and German Ulrich Haas.
A statement from Cas read: "The panel found that there were no established facts that would elevate the possibility of meat contamination to an event that could have occurred on a balance of probabilities.
"In the panel's opinion, on the basis of the evidence adduced, the presence of clenbuterol was more likely caused by the ingestion of a contaminated food supplement."
UCI president Pat McQuaid said: "This is a sad day for our sport. Some may think of it as a victory, but that is not at all the case."There are no winners when it comes to the issue of doping: every case, irrespective of its characteristics, is always a case too many."
REFC president Juan Carlos Castano said: "It's very bad news for Spanish sport. For us this journey has ended."
And British cyclist Mark Cavendish - the winner of the green jersey for top sprinter in the 2011 Tour de France - added on Twitter: "Regardless of the outcome for Contador, I just wish, for the sake of our sport & everyone in it, that a decision had been made sooner.
'Unjust, excessive and difficult to understand' is one of the headlines on the website of the Spanish Newspaper El Pais. It sums up the general mood in the Spanish media.
And in the Barcelona-based La Vanguardia, they quote Perico Delgado, who won the Tour in 1988 as saying that 'they (the International Cycling Federation) are losing their focus in the fight against doping.'
A winner of the Tour in 2007 and 2009, he becomes only the second cyclist to lose his title for doping, after American Floyd Landis tested positive for testosterone in 2006.
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.