Yusuke Kawaguchi (川口雄介, Kawaguchi Yusuke) (born August 14, 1980) is a Japanese mixed martial artist and professional wrestler, who fights in the heavyweight division. He is the former DEEP Megaton Champion, and has also fought in DREAM, M-1 Global and KSW.
Yusuke Kawaguchi came in third place at the high school-level national Judo championships and third place at the 1999 University Judo Championships in the 100 kg weight class.
Kawaguchi made his mixed martial arts debut on April 13, 2007 at DEEP: 29th Impact and defeated his opponent Hirotaka Fujiyama by majority decision. He went on to win his next two fights by way of knockout in the first round and in 2008, he took part in the DEEP Megaton Grand Prix. He TKO'd Nobuyoshi Takahara in the preliminary round and advanced to the quarter-finals where he faced former sumo wrestler Wakashoyo. Wakashoyo rushed Kawaguchi at the beginning of the fight and was knocked out after just 16 seconds. Kawaguchi then advanced to the final stage, where the semi-finals and final were held in one night. In the semis, he came up against Shunji Kosaka, and beat him after his corner threw in the towel within 45 seconds of the first round. Shunsuke Inoue was then to be his opponent in the final. After two four-minute rounds, Kawaguchi emerged the victor by way of split decision to become the DEEP Megaton Champion.