Dutch bank Rabobank will end their sponsorship of professional cycling from December 31 following the Lance Armstrong doping revelations.
The United States Anti-Doping Agency last week published an extensive report into allegations against Armstrong, concluding that he engaged in "serial cheating" and his US Postal Service team ran "the most sophisticated, professionalised and successful doping programme that sport has ever seen".
Bert Bruggink, a member of Rabobank's managing board, said: "It is with pain in our heart, but for the bank this is an inevitable decision. We are no longer convinced that the international professional world of cycling can make this a clean and fair sport. We are not confident that this will change for the better in the foreseeable future."
A statement on rabosport.com confirmed that the firm will continue with its sponsorship deals in amateur cycling but will sever ties with both their men's and women's professional teams.
The announcement comes a day after the team suspended their Spanish rider Carlos Barredo after the International Cycling Union (UCI) launched a doping case against him.
Former team member Levi Leipheimer, one of 11 former team-mates of Armstrong who testified against him to the US anti-doping agency (USADA), said he took EPO while with Rabobank assisted by their team doctor. He also testified that other members of the Rabobank team used banned substances.
British cyclist David Millar criticised the bank's decision, saying on Twitter: "Dear Rabobank, you were part of the problem. How dare you walk away from your young clean guys who are part of the solution. Sickening."
The Rabobank team have accrued 23 Tour de France stage wins since their sponsorship began in 1996, most recently by Luis Leon Sanchez in Saint-Flour in 2011.
They looked set for overall victory in 2007 when Michael Rasmussen won nine stages, but the Dane was then withdrawn from the race and sacked by the team after lying about his whereabouts when he missed drug tests in the build-up to the tour. Rasmussen served a two-year ban, returning in July 2009.
Denis Menchov won two Vuelta a Espana titles for the team, in 2005 and 2007, as well as the 2009 Giro d'Italia, while Sanchez won this year's Paris-Nice.