Koreshkov made his professional mixed martial arts debut in October 2010. He initially competed exclusively in his native Russia and compiled an undefeated record of 8-0 with none of his fights going to a decision. The MMA news siteBloody Elbow listed Koreshkov as the top welterweight prospect in their 2012 MMA scouting report.
In January 2012, it was announced that Koreshkov would make his United States debut for Bellator.
In his debut, Koreshkov faced Tiawan Howard on March 30, 2012 at. He won via KO in the first round. Andrey next faced Derrick Krantz on May 18, 2012 at. He won the fight via TKO in the third round. Andrey then faced Jordan Smith on September 28, 2012 at. He defeated Smith after 3 rounds, earning Koreshkov won a unanimous decision victory. In the semifinals of the tournament, Koreshkov won via Technical Knockout, defeating Marius Zaromskis in the first round. Koreshkov faced Lyman Good in the final of the tournament and won via unanimous decision. Koreshkov faced Ben Askren in a bout for the Bellator Welterweight Championship on July 31, 2013 at Bellator 97. He lost the fight via TKO in the fourth round. In March 2014, Koreshkov entered the. He faced Nah-Shon Burrell in the quarterfinal match on March 14, 2014 at Bellator 112. He won the fight via TKO during the first minute of the first round. Koreshkov was expected to face Sam Oropeza on May 2, 2014 in Welterweight tournament finals at Bellator 118. Oropeza, however, was injured and replaced by Justin Baesman. Koreshkov won via knockout due to a flying knee in the first round. In the finals, Koreshkov met Adam McDonough at Bellator 122 on July 25, 2014. He won the fight via unanimous decision, securing his second tournament win and title shot. Koreshkov faced Douglas Lima for the Bellator Welterweight Championship at Bellator 140 on July 17, 2015. He won the fight by unanimous decision to become the new Bellator Welterweight Champion. Koreshkov faced former UFC Lightweight ChampionBenson Henderson on April 22, 2016 at the Bellator 153. He dominated the fight, winning a unanimous decision and scoring his first title defense as the Bellator welterweight champion. Koreshkov faced Douglas Lima in a rematch in the main event at Bellator 164 on November 10, 2016. He lost the fight by knockout in the third round. Koreshkov was scheduled to face Fernando Gonzalez on March 3, 2017 at Bellator 174. However, Koreshkov pulled out of the fight due to injury. Koreshkov faced Chidi Njokuani at Bellator 182 on August 25, 2017. He won the fight in the first round via a combination of punches and elbows. Koreshkov faced Vaso Bakočević at Bellator 203 on July 14, 2018. He won the fight via knockout due to a spinning back kick to Bakocevic's mid-section early in the first round. Koreshkov faced Douglas Lima in a third match as part of the opening round of the Bellator Welterweight World Grand Prix on September 29, 2018 at Bellator 206. He lost the fight via a rear-naked choke in the fifth round. Koreshkov was expected to headline Bellator 219 against Lorenz Larkin on March 29, 2019. However, Larkin withdrew from the bout citing an injury and was replaced by Mike Jasper. Koreshkov won the fight via unanimous decision. The bout with Larkin eventually took place at Bellator 229 on October 4, 2019. Koreshkov lost the back-and-forth fight via split decision.
