Sergei Postrekhin (born November 1, 1957, in Kherson, Ukrainian SSR) is a Soviet-born Ukrainian sprint canoer who competed in the late 1970s and early 1980s. At the 1980 Summer Olympics in Moscow, he won a gold in the C-1 500 m event and a silver in the C-1 1000 m event.
Postrekhin also won three medals at the ICF Canoe Sprint World Championships with a gold (C-1 500 m: 1979) and two bronzes (C-1 500 m: 1982, C-2 1000 m: 1978).