Stage races One-day races and Classics Kanstantsin Sivtsov (or Siutsou[2] (Belarusian: Канстанцін Віктаравіч Сіўцоў; Łacinka: Kanstancin Viktaravič Siŭcoŭ; born 9 August 1982) is a Belarusian former professional road bicycle racer, who rode professionally between 2001 and 2018 for the Itera, Lokomotiv, Fassa Bortolo, Acqua & Sapone, Barloworld, HTC–Highroad, Team Sky, Team Dimension Data and Bahrain–Merida squads.

He retired after provisionally being suspended from the sport following an adverse analytical finding for erythropoietin (EPO).

Sivtsov joined Barloworld for the 2007 season, and rode the Tour de France, finishing 32nd overall.

[6] On 5 September 2018, the UCI announced that an out of competition test had resulted in an adverse analytical finding of Erythropoietin in a sample collected 31 July 2018.

[7] This followed his back injury sustained whilst carrying out a recon of the time trial at the Giro earlier that year.