The following is an incomplete list of doping cases and recurring accusations of doping in professional cycling, where doping means "use of physiological substances or abnormal method to obtain an artificial increase of performance". It is neither a 'list of shame' nor a list of illegality, as the first laws weren't passed until 1965 and their implementation is an ongoing developing process. Thus the list contains doping incidents, those who have tested positive for illegal performance-enhancing drugs, prohibited recreational drugs or have been suspended by a sporting body for failure to submit to mandatory drug testing. It also contains and clarifies cases where subsequent evidence and explanation has shown the parties to be innocent of illegal practice.

In 1963 the Council of Europe gave a definition of doping.

"Doping means to make use of physiological substances in immoderate quantity or abnormal method from healthy people whose only aim is to obtain an artificial increase of the performance during the competition". or ...

Lance Edward Armstrong (born Lance Edward Gunderson on September 18, 1971) is an American former professional road racing cyclist who won the Tour de France a record seven consecutive times after having survived testicular cancer. He is also the founder and chairman of the Lance Armstrong Foundation for cancer research and support. He last rode for UCI ProTeam Team RadioShack, a team he helped found.

In October 1996 he was diagnosed as having testicular cancer with a tumor that had metastasized to his brain and lungs. His cancer treatments included brain and testicular surgery and extensive chemotherapy, and his prognosis was originally poor. He went on to win the Tour de France each year from 1999 to 2005, and is the only person to win seven times having broken the previous record of five wins shared by Miguel Indurain, Bernard Hinault, Eddy Merckx, and Jacques Anquetil.

In 1999, he was named the ABC Wide World of Sports Athlete of the Year. In 2000 he won the Prince of Asturias Award in Sports. In 2002, Sports Illustrated magazine named him Sportsman of the Year. He was also named Associated Press Male Athlete of the Year for the years 2002–2005. He received ESPN's ESPY Award for Best Male Athlete in 2003, 2004, 2005, and 2006, and won the BBC Sports Personality of the Year Overseas Personality Award in 2003. Armstrong announced his retirement from racing on July 24, 2005, at the end of the 2005 Tour de France but returned to competitive cycling in January 2009 and finished third in the 2009 Tour de France. He confirmed he had retired from competitive cycling for good on February 16, 2011.

Alberto Contador Velasco (Spanish pronunciation: [alˈβerto kontaˈðor βeˈlasko]; born 6 December 1982) is a Spanish professional road bicycle racer, who last rode for UCI ProTeam Team Saxo Bank. He was the winner of the 2007 Tour de France with the Discovery Channel team. With the Astana team he has won the 2008 Giro d'Italia, the 2008 Vuelta a España and the 2009 Tour de France. He initially also won the 2010 Tour de France with this team, and the 2011 Giro d'Italia with team Saxo Bank-SunGard, only to be stripped from these titles later having been found guilty of a doping offence. He is the fifth racer in history, and the first Spaniard, to win all three Grand Tours of road cycling.

Contador is widely considered to be the best climbing specialist and stage racer in the world. Notable summit stage finishes on which he has victories include the Alto de El Angliru in the Vuelta, the Plateau de Beille in the Tour and Mount Etna in the Giro. After being widely expected to lose his tenuous lead in the 2007 Tour de France in that race's final individual time trial, Contador has become a more accomplished time trialist, with several victories in the discipline. He has earned a reputation as an all-rounder, a cyclist who excels in all aspects of stage racing which are needed for high places in the general classification.

George Hincapié Garcés (born June 29, 1973 in Queens, New York) is an American professional road bicycle racer currently riding for UCI ProTeam BMC Racing Team. Hincapie resides in Greenville, South Carolina. He graduated from Farmingdale High School in 1991.

Hincapie is most widely known as a key domestique of Lance Armstrong, having been the only rider to assist Armstrong in all seven of his Tour de France victories. Hincapie was also a domestique for Alberto Contador in 2007 and for Cadel Evans in 2011, when both men won the Tour de France. He is one of only two riders in Tour de France history to have raced on nine Tour-winning teams. As of the end of the 2011 Tour, Hincapie has raced the Tour 16 times, finishing all but the first year.

Hincapie has several important wins of his own, starting with Gent–Wevelgem in 2001 and Kuurne–Brussels–Kuurne in 2005. Also in 2005, Hincapie took two stage wins at the Critérium du Dauphiné Libéré and 2nd place at Paris–Roubaix. In 2005 he also had his first stage win in the Tour de France where, on July 17, he finished seven seconds ahead of Óscar Pereiro to win stage 15 from Lézat-sur-Lèze to Pla d'Adet. More recent victories include two stages at the Tour of California (2006), the overall and a stage at the Tour of Missouri (2007), and another stage win at the Critérium du Dauphiné Libéré in 2008. He is a three-time US Professional Road Race champion (1998, 2006, 2009).

Gregory James LeMond (born June 26, 1961 in Lakewood, California) is a former professional road bicycle racer from the United States and a three-time winner of the Tour de France. He was born in Lakewood, California and raised in Reno, Nevada.

In 1986, LeMond became the first American and the first non-European cyclist to win the Tour de France. The following year he was shot and seriously injured in a hunting accident. He was able to return to the Tour in 1989, winning it dramatically in its final stage. He won again for the third time the following year in 1990. He is one of only nine cyclists to have won the Tour three or more times.

Greg LeMond was a standout junior rider who quickly established himself as one of the most talented cyclists in the professional circuit. After his initial success on the junior circuit he began competing against older, more seasoned competitors. He gained the attention of the US Cycling Federation's national team, riding for them at the 1979 Junior World Championships held in Argentina. There he won gold, silver and bronze medals, the highlight being his spectacular victory in the road race. He was selected for the 1980 U.S. Olympic cycling team, the youngest ever, at 18, to make the U.S. team; however, the U.S. boycott of the 1980 Summer Olympics in Moscow prevented him from competing there.