Chester Morris as Dr. Carlo Lombardi

Marla English as Andrea Talbott / Elizabeth Wetherby

Tom Conway as Timothy Chappel

Cathy Downs as Dorothy Chappel

Lance Fuller as Dr. Ted Erickson

Ron Randell as Police Lt. Ed James

Frieda Inescort as Mrs. Chappel

Frank Jenks as Plainclothes Sgt. with Lt James

El Brendel as Olaf, the butler

Paul Dubov as Johnny, the barker

William Hudson as Bob, the ex-fiancé

Flo Bert as Marta, the Maid

Jeanne Evans as Mrs. Brown

Kenneth MacDonald as Police Doctor with Prof. Anderson

Jack Mulhall as Lombardi's Lawyer

Edward Earle as Professor Anderson

Bess Flowers as Party Guest

Paul Blaisdell as The She-Creature

Spike as King the Dog