[3] His major victories include winning the 2007 Monte Paschi Eroica, a stage of the 2007 Paris–Nice and he is a two-time winner of the Russian National Road Race Championships.

He won the third stage of Paris–Nice, became the inaugural winner of the Monte Paschi Eroica, now known as Strade Bianche,[7] and finished second at the UCI Road World Championships.

Second-place finisher Davide Rebellin later tested positive for Continuous erythropoietin receptor activator (CERA), causing the IOC to strip him of his silver medal.

[8][9] In the 2011 Tour de France he tested positive for the diuretic hydrochlorothiazide, a masking agent that can hide the presence of performance-enhancing drugs.

[3] In 2012, the Union Cycliste Internationale initiated an investigation of Kolobnev and the Kazakh rider Alexander Vinokourov over allegations brought by the Swiss news magazine L'lllustre and Italian newspaper Corriere della Sera.