Christian Poswiat (born 26 June 1968) is a German swimmer who won two bronze medals in medley relays at the 1987 European Aquatics Championships and 1991 World Aquatics Championships. He also competed at the 1988 and 1992 Summer Olympics in the 100 m and 200 breaststroke; his best achievement was eighth place in the 100 m event in 1988.