Demir Atasoy (also Dmitry Cherkasov, born May 26, 1987, in Dnipropetrovsk, Ukrainian SSR) is a Ukrainian-born Turkish swimmer, who specialized in the breaststroke events.

[2] Atasoy qualified for the men's 100 m breaststroke at the 2008 Summer Olympics in Beijing, by clearing a FINA B-standard time of 1:02.43 from the Croatian Open Championships in Dubrovnik.

[3] He challenged seven other swimmers on the fourth heat, including three-time Olympian Jakob Jóhann Sveinsson of Iceland.

Atasoy edged out Serbia's Čaba Silađi to take the second spot by six hundredths of a second (0.06), posting his lifetime best of 1:02.25.

[5] At the 2013 Mediterranean Games held in Mersin, Turkey, he won the bronze medal in the men's 4 × 100 m medley relay.