Koji Alexander Murofushi (室伏 アレクサンダー 広治 Murofushi Arekusandā Kōji?, born October 8, 1974 in Numazu, Shizuoka Prefecture) is a Japanese hammer thrower. He has been among the world elite since the 2001 World Championships, where he won the silver medal, and also he won the gold medal in Athens Olympics.
Koji Murofushi comes from a hammer throwing family, as his father Shigenobu Murofushi is a former Olympian and held the Japanese record for 23 years until his son broke it, and his sister, Yuka Murofushi, throws both hammer and discus. Murofushi's Romanian-born mother, Serafina Moritz, was a javelin thrower for Romania, European Junior champion in 1968, and Romanian senior champion in 1970.[9][10][11] She is now a glass painter, and lives in Toyota, Aichi Prefecture.[12]