The German rode alongside Jan Ullrich, Alberto Contador and Lance Armstrong, winning eight pro stage races including Paris-Nice, Tirreno-Adriatico, Tour of Romandie and the Tour of the Basque Country on two occasions. He also claimed a bronze medal at the Olympic Games in Sydney in 2000.
Kloeden has faced doping allegations, but told the Weser-Kurier, "I have nothing to confess."
He was implicated in an independent commission's 2009 investigation into an alleged doping system at Freiburg University Clinic between 1995 and 2006 for the former Team Telekom, later known as T-Mobile.
Kloeden was suspected of receiving illegal transfusions of his own blood in July 2006, but he vehemently denied any wrongdoing.