Armstrong has won the Tour de France seven times
Lance Armstrong's hopes of riding in the Tour de France have improved after anti-doping officials decided not to take action over a disputed drugs test.
French doctors tested Armstrong's hair, urine and blood on 17 March, finding no traces of drugs.
France's anti-doping agency (AFLD) initially said Armstrong had not fully co-operated with testers.
But the AFLD said it would not open disciplinary procedures after receiving written evidence from Armstrong.
"The analysis of the urine and blood samples from Mr Armstrong did not reveal any abnormality. His hair sample has not been tested," read the statement.
Case closed, no penalty, all samples clean. Onward.
Lance Armstrong on his Twitter feed
Armstrong admitted he feared the agency would ban him from taking part in this year's Tour - starting in Monaco on 4 July - which would be his first after a three-year absence.
The seven-time Tour winner was clearly relieved as he responded to Friday's announcement on social networking site Twitter.
"Just got the word from the French agency AFLD on the shower gate incident," he wrote. "Case closed, no penalty, all samples clean. Onward."
At issue was a 20-minute delay when Armstrong said the tester agreed to let him shower while the Astana rider's assistants checked the tester's credentials.
A doctor submitted a report to the AFLD saying Armstrong had violated anti-doping rules. In response Armstrong then sent a letter to the AFLD on 16 April explaining his position.
Armstrong, who is currently recovering from surgery after breaking his collar bone, is hoping to line up for the Tour of Italy, which starts on 9 May and is now embarking on a 10-day training programme in Aspen, Colorado.