CAS also ruled that all of Ullrich's results since May 1, 2005, be annulled.

The German, who retired in November 2007, thus sees his third-placed finish in the 2005 Tour de France written off.

"The CAS has partially upheld the appeal filed by the UCI (International Cycling Union) and has found Jan Ullrich guilty of a doping offence," CAS said.

"As a consequence, Jan Ullrich is sanctioned with a two-year period of ineligibility starting retroactively on August 22, 2011. Furthermore, all results achieved by the athlete on or after May 1, 2005, until his retirement are annulled."

CAS said, "Given the volume, consistency and probative value of the evidence presented by the UCI, and the failure of Ullrich to raise any doubt about the veracity or reliability of such evidence, this panel is satisfied beyond its comfortable satisfaction that Ullrich engaged at least in blood doping in violation of Article 15.2 of the UCI Rules."

The CAS hearing came about after the UCI appealed to the court against the Swiss Olympic Committee's decision to halt an investigation into Ullrich's past.

The Swiss Olympic committee, with whom Ullrich had a licence, had decided not to pursue the investigation about Ullrich, who lived in Switzerland, because the German resigned from the Swiss cycling federation in 2006.

Ullrich, the former T-Mobile lead rider, was linked to the Operation Puerto scandal in 2006 after samples of his blood were found during a police raid on Spanish doctor Eufemiano Fuentes who was at the centre of a doping ring.

Ullrich has always insisted he is innocent and has never doped.