John Carradine

Dr. Sigmund Walters

Evelyn Ankers

Beth Colman

Milburn Stone

Fred Mason

Lloyd Corrigan

John Whipple

Fay Helm

Nurse Strand

Martha Vickers

Dorothy Colman

Acquanetta

Paula Dupree, the Ape Woman

Vince Barnett

Curly

Paul Fix

Gruen

Fred Aldrich

Roustabout (uncredited)

Clyde Beatty

Fred Mason (in long shots) (archive footage / uncredited)

Turhan Bey

End Narrator (voice)(uncredited)

Eddie Borden

Dock Spectator (uncredited)

Ray Corrigan

Cheela the Gorilla (uncredited)

Russell Custer

Curley (uncredited)

Edward Dmytryk