Igor Vovchanchyn transitioned from a successful kickboxing career to MMA in 1995. He competed primarily in tournament-style events across the Ukraine, often fighting three or four times in one day. Often he is famed for being one of the few strictly stand-up fighters to successfully overcome grappling opponents. This was seen in the very first IAFC event in which he managed to defeat Adilson Lima; a Gracie Jiu Jitsu black belt who trained with Ryan Gracie. First ending the fight with a knockout :56 seconds into the fight, however Lima's corner Relson Gracie argued to the tournament organizers complaining that the kicks to a downed opponent were unfair and demanded an immediate rematch. Strangely enough the rematch was granted, and the fight began again with Lima being a more cautious fighter this time around. However the fight was stopped a second time as a result of a broken nose from a punch thrown by Vovchanchyn; ultimately ending the fight. He accumulated a 22-1-1 record before joining PRIDE Fighting Championship, including a 21-fight unbeaten streak.

His first opponent in PRIDE was Gary "Big Daddy" Goodridge who Igor defeated via TKO. Igor's unbeaten streak persisted until the finals of the 2000 PRIDE Open Weight Grand Prix, where he was defeated by Mark "The Hammer" Coleman by Submission (Strikes), ending his 30-fight winning streak.