U.S. Anti-Doping Agency (USADA)

Click here to log in to the
Athlete Connect application

Click here to log in to
Athlete Express

USADA logo with registered symbol.

Global DRO logo in whiteSearch Medications & Ingredients

Close this search box.


The United Sates Anti-Doping Agency (USADA) announced today the decision of an independent three-member arbitration panel from the International Court of Arbitration for Sport (CAS), the highest court for sport.  The CAS Panel confirmed the lower court’s decision and imposed a two year suspension on Tyler Hamilton of Boulder, Colo., one of the top contenders in the 2004 Tour de France and the gold medal winner in the time trial at the 2004 Athens Olympic Games, for committing a doping violation.

Following full evidentiary hearings, the CAS Panel unanimously found that Mr. Hamilton, 34, committed a doping violation for testing positive for transfusing another person’s blood.  The CAS Panel stated, “USADA has met its burden of proof by demonstrating that the HBT test conducted by the Lausanne Laboratory was in accordance with the scientific community’s practice and procedures.”

The CAS Panel heard from numerous witnesses which included the independent expert testimony of one of the world’s top flow cytometrist, Dr. Bruce Davis of the Maine Medical Center Research Institute, who is also the Chairman of the Clinical and Laboratory Standards Institute Area Committee in Hematology.  Dr. Davis’ evidence was that “without any equivocation . . . the blood sample from Tyler Hamilton on September 11, 2004 contained a mixed population . . . indicat[ing] a previous homologuous blood transfusion.”

In reaching its decision the CAS Panel considered a number of Mr. Hamilton’s theoretical explanations for the positive test result including a disappearing twin, unsubstantiated problems with his positive test results and even an extortion plot by a fan of another team.

“The Panel considered each of the excuses and found each to be completely without merit,“ said Terry Madden, CEO of USADA.  “It is sad that Mr. Hamilton resorted to conspiracy theories rather than just accept the consequences of his doping.”

Madden added, “the development and implementation of this test and the confirmation of its validity would not have been possible without the dedication and efforts of the scientific community and the world anti-doping movement.”

A transfusion of another person’s blood is a prohibited method under the USADA Protocol and the UCI Anti-Doping Rules, which adopt the World Anti-Doping Code and the World Anti-Doping Agency’s Prohibited List.  This form of blood doping allows a person to increase their red blood cells, thereby increasing their aerobic power and endurance.

Hamilton tested positive at the Vuelta de Espana on September 11, 2004 and forfeits all competitive results received from that date.  His period of suspension ends on September 22, 2006, two years from the day the CAS Panel found he was provisionally suspended.

Union Cycliste Internationale (UCI) initially referred the case to USADA for handling.  UCI joined USADA as a party in the presentation of the case when Mr. Hamilton appealed the initial arbitration decision.

View The AAA Decision PDF
View The Decision PDF

USA Cycling, the national governing body for the sport in the United States, will carry out the sanction.

USADA is responsible for managing the testing and results management process for athletes in the U.S. Olympic and Paralympic Movement.  USADA is equally dedicated to preserving the integrity of sport through research initiatives and educational programs.

For more information or media inquiries, click here.

Scroll to Top