Bela Lugosi as Dr. James Brewster

Louise Currie as Billie Mason

Wallace Ford as Jeff Carter

Henry Hall as Dr. George Randall

Minerva Urecal as Agatha Brewster

Emil Van Horn as The Ape

J. Farrell MacDonald as Captain O'Brien

Wheeler Oakman as Brady

Ralph Littlefield as Zippo

Jack Mulhall as Reporter

Charles Jordan as O'Toole

Charlie Hall as Barney