Luca Paolini has been banned for 18 months by the Union Cycliste Internationale (UCI) after failing a drugs test at the Tour de France last year.
The 39-year-old former Katusha rider was provisionally suspended by the UCI after testing positive for cocaine during the prestigious race in 2015.
Italian Paolini, who won the Gent-Wevelgem last year, discovered his fate following a UCI tribunal.
A UCI statement said: "The Union Cycliste Internationale (UCI) announces that the UCI Anti-Doping Tribunal has rendered its decision in the case involving Luca Paolini.
"The Anti-Doping Tribunal found the rider guilty of a non-intentional anti-doping rule violation (presence of a cocaine metabolite - benzoylecgonine) and imposed an 18-month period of ineligibility on the rider."
The UCI did not state whether Paolini's ban will be backdated to when he failed the test.
Katusha terminated the veteran's contract last year after he admitted to taking cocaine.