Peter Cushing

Dr. Victor Stein

Francis Matthews

Dr. Hans Kleve

Eunice Gayson

Margaret Conrad

Michael Gwynn

Karl

John Welsh

Bergman

Lionel Jeffries

Fritz

Oscar Quitak

Dwarf

Richard Wordsworth

Up Patient

John Stuart

Inspector

Michael Ripper

Kurt

Charles Lloyd Pack

President

Arnold Diamond

Molke

Marjorie Gresley

Countess Barscynska

Anna Walmsley

Vera Barscynska

George Woodbridge

Janitor

Ian Whittaker

Boy

Avril Leslie

Girl

John Tatham

Manservant (uncredited)

Eugene Leahy

Kleine (uncredited)

Charles Gilliard

Policeman (uncredited)

Jimmy Charters

Patient (uncredited)

Julia Nelson

Inga (uncredited)

Robert Brooks Turner

Joseph the Groom (uncredited)