Born in Andijan, Uzbekistán, on October 19, 1978. During his amateur period he stood out in the World Championships of 1997 and 2001, also in the Felix Savon tournament which he later lost.

Participated in the Atlanta 1996 and Sydney 2000 Olympic Games. Curiously, he made his professional debut in 1997, but continued attending different amateur tournaments. Reappeared in the professional circuit at the end of 2001, and after 23 undefeated wins, he had the chance to opt for the WBA heavyweight championship before Nicolay Valuev, whom he defeated by unanimous decision in 2007.

Matt Skelton was his first rival as world champion. After that there came a long period of injuries. He was stripped of his WBA title in 2009.

He is the regular heavyweight champion since july 6, 2014, when he defeated Fres Oquendo by majority decision. In july 2015 he defended against Francesco Pianneta, beating him by KO.

Changaev went to face Australian Lucas Browne, to whom he lost by TKO. However, Browne gave positive in his Sample A antidoping control.

When losing the fight against Lucas Browne by TKO in Russia in March 2016 , the Russian was defending his world crown.

After the prohibitted substances control tests, Browne gave positive to clembuterol in his Sample A. After that, Chagaev was reinstated as the division champion and Browne was suspended for 6 months.

Now Chagaev must face Fres Oquendo as part of the heavyweight category tournament. (DATE).