Italian rider Emanuele Sella has tested positive in an out-of-competition doping control, the Italian cycling federation has said.
A federation spokeswoman said the test was carried out by the International Cycling Union but did not say what substance Sella had tested positive for.
The UCI could not be reached for comment.
The 27-year-old, who is not competing in the Beijing Olympics, told ANSA news agency he was unaware of the positive test.
"I know absolutely nothing about this story. No one has told me anything. None of it is true," he said.
Sella won three stages of this year's Giro d'Italia riding for CSF Group-Navigare.
A federation spokeswoman said the test was carried out by the International Cycling Union but did not say what substance Sella had tested positive for.
The UCI could not be reached for comment.
Cycling has been hit by a series of doping controversies with Italian riders often involved.
Riccardo Ricco, a reserve for the Beijing team, admitted to taking the blood booster EPO during last month's Tour de France and has been suspended.
Women's cycling road race world champion Marta Bastianelli will also not be going to the Olympics after testing positive for a stimulant which she says she did not know was in a diet product.
She attended a hearing with Italy's anti-doping prosecutor on Tuesday and later said she hoped the matter had been cleared up.
Bastianelli is now waiting to see if she will be banned or will be allowed to defend her world title in Varese, Italy next month.
Reuters
