James Williams Melenchuk (born June 24, 1953) is a Canadian former politician. He represented the electoral district of Saskatoon Northwest in the Legislative Assembly of Saskatchewan from 1999 to 2003. He was educated at the University of Regina and the University of Saskatchewan and practised medicine in Saskatoon. Melenchuk stepped down as Liberal leader in 2001, and was succeeded by David Karwacki. In 2005, Melenchuk was named academic health sciences liaison between the Saskatchewan government and the University of Saskatchewan.