Armstrong will race for the Astana team in Australia
Lance Armstrong has been cleared to make his cycling comeback in January's Tour Down Under in Australia.
The International Cycling Union (UCI) demands riders coming out of retirement need to be in their anti-doping regime for six months before racing again.
That would have made Armstrong, 37, who also plans to ride in the 2009 Tour de France, ineligible until 1 February.
But the UCI has made an exception to its rules, saying improved drug-testing standards means he can return early.
In a statement, the UCI said: "The aim of the ruling can be better achieved through careful application of the current methods of the anti-doping programme than by the strict application of a time period.
"The UCI can confirm Lance Armstrong has and will be the subject of very strict monitoring throughout the period running up to his return to the peloton."
The Tour Down Under, from 20-25 January, will be Armstrong's first road race for three years.
Armstrong had to return to the United States Anti-Doping Agency's testing programme to compete in August's Leadville Trail 100 mountain bike race in Colorado.
The seven-time Tour de France champion filed papers with the US Anti-Doping agency on 1 August and claims he was tested in late August.
Armstrong has also said he plans to race in the Tour of California in February and the Tour in July, while he has also mentioned the Paris-Nice race, a race in South Africa, and the Giro d'Italia as other possible 2009 events.