Alexandre Vinokourov has announced his retirement in the wake of the one-year doping ban he received from the Kazakhstan cycling federation.
Vinokourov was third in the 2003 Tour de France
Vinokourov, 34, and his Astana team were kicked out of the 2007 Tour de France after he tested positive for a banned blood transfusion.
He was fired by Astana after his B sample confirmed the positive result.
"I don't want this sport any more. I'm slamming the door and I'm leaving. I will prove I'm not guilty," he said.
"I want to restore my honour and get the results of this test rescinded."
Vinokourov was third in the 2003 Tour de France, fifth in 2005, and had been tipped to win this year's race.
A bad crash left him trailing the leaders, but he won a time trial and mountain stage before falling foul of the doping testers.
At the time, he said: "It's a mistake. I have never doped, that's not the way I see my profession."
Before their withdrawal, Astana had been leading the team standings and had Andreas Kloeden in fifth place and Andrey Kashechkin in eighth.