Federal prosecutors in the United States have dropped their investigation into allegations of doping at a professional cycle racing team which is partly owned by Lance Armstrong.
A grand jury in Los Angeles had been hearing evidence from former teammates and associates of the cycling legend.
United States Attorney Andre Birotte said media speculation meant a public announcement was necessary.
Lance Armstrong has always denied taking drugs.
He won the Tour de France for seven consecutive years from 1999-2005.
The cancer survivor retired from competitive cycling for the second time in 2011.
Several former fellow cyclists on the US Postal team have come forward to claim that the former champion used performance-enhancing substances.
Responding to the news that the inquiry has been closed, Mr Armstrong's lawyer Mark Fabiani said that the cyclist was pleased that prosecutors "made the right decision," and that he was "determined to devote his time and energy" to his cancer foundation Livestrong, the Associated Press news agency reports.