Uberlino Mesa and Jure Golcer have been forbidden from competing in this year's Giro d'Italia after irregular findings in their pre-race medical checks.
The duo took part in the routine tests like every rider in the race, which starts on Saturday.
But they were banned from competing by the International Cycling Union.
A statement from cycling's official body said: "The result of these tests have shown these two riders have irregular findings."
The 32-year-old Mesa, from Colombia, had been part of the Selle Italia-Colombia team, while Slovenia's Golcer, 26, is in the Pinzolo team.