Mark Edmund "Duke" Bainum (July 21, 1952 – June 9, 2009) was an American politician and physician. Bainum served in the Hawaii State House of Representatives as a member of the Hawaii Democratic Party and was elected in a nonpartisan race to the Honolulu City Council and held various committee chairmanships during his tenure. In 2004, Bainum ran for Mayor of Honolulu in the state of Hawaii, but lost to former White House Aide Mufi Hannemann. Bainum was married to Jennifer Toma Bainum.