The Mad Doctor

Basil Rathbone

Dr. George Sebastian / Dr. Langamann

Ellen Drew

Linda Booth

John Howard

Gil Sawyer

Barbara Jo Allen

Louise Watkins (as Barbara Allen [Vera Vague])

Ralph Morgan

Dr. Charles Downer

Martin Kosleck

Maurice Gretz

Kitty Kelly

Winnie

Hugh O'Connell

Lawrence Watkins

Henry Victor

Furber (Uncredited)

Wanda McKay

Girl at Charity Bazaar (Uncredited)

James Seay

Intern (Uncredited)

William Benedict

Mickey Barnes (Uncredited)

George Chandler

Elevator Operator (Uncredited)

Edward Earle

Librarian (Uncredited)