Ernest Charles "Butch" Deadmarsh (born April 5, 1950 in Trail, British Columbia) is a former ice hockey left wing. He was drafted in the second round, 15th overall, of the 1970 NHL Amateur Draft by the Buffalo Sabres. He played in the National Hockey League for the Sabres, Atlanta Flames, and Kansas City Scouts. He also played in the World Hockey Association for the Vancouver Blazers, Calgary Cowboys, Minnesota Fighting Saints, Edmonton Oilers, and Cincinnati Stingers. He is the uncle of former NHL player Adam Deadmarsh.
In his NHL career, Deadmarsh played in 137 games, scoring twelve goals and adding five assists. He played in 255 WHA games, scoring 63 goals and adding 66 assists.