Kitajima Kosuke (born September 22, 1982 in Arakawa) is a Japanese multiple Olympic gold medalist breaststroke swimmer. He won gold medals for the men's 100 m and 200 m breaststroke at both the Athens 2004, and the Beijing 2008 Summer olympic games.
Kitajima is a decorated swimmer in the world championships and was the world record holder in the 100 m breaststroke that he set in the 2008 Beijing Olympics – this mark has since been bettered by first Brenton Rickard and later Cameron van der Burgh. He is also bronze medal winner in the same Olympics in the 4×100 m medley relay. He edged out his main rival Brendan Hansen who finished fourth while Kitajima won the gold medal and set the new world record.
His most significant rival in the breaststroke was the American swimmer Brendan Hansen. They dueled at events such as the 2005 World Championships, 2004 Summer Olympics and 2003 World Championships. Kitajima set both world records for 100 m and 200 m breaststroke in the latter occasion. Later his best in 200 m was overcome by Dimitri Komornikov and then by Hansen, who also broke Kitajima's record in the 100 m. Kitajima regained the world record (58.91) in the 100 m at the 2008 Summer Olympics. Kitajima regained the 200 m breaststroke world record in June 2008 at the Japan Open. His time of 2:07.51 shaved nearly a second off the previous record of 2:08.50 set by Hansen in 2006.
During the 2004 Olympic Games in Athens, Kitajima generated buzz for his primal screams of exuberance after edging out Hansen in the 100 m and 200 m breaststroke for the gold. At a pool side interview (3'24") following his victory in the 100 m, Kosuke Kitajima also popularised the phrase 'cho-kimochi-ii,' meaning "I feel really good." The word went on to win the 2004 U-Can Neologisms and Vogue Words contest.