Christopher Lee
Prof. Sir Alexander Saxton
Peter Cushing
Dr. Wells
Telly Savalas
Captain Kazan
Alberto de Mendoza
Father Pujardov
Silvia Tortosa
Countess Irina Petrovska
Julio Peña
Inspector Mirov
Ángel del Pozo
Yevtushenko
Helga Liné
Natasha
Alice Reinheart
Miss Jones
José Jaspe
Conductor Koniev
George Rigaud
Count Maryan Petrovski
Víctor Israel
Luggage Worker
Faith Clift
American Passenger, Miss Bennett (uncredited)
Juan Olaguibel
Creature
José Marco
Vorkin
José Canalejas
Russian Guard
Vicente Roca
Station Master
Hiroshi Kitatawa
Grashinski - the Locksmith (uncredited)
Barta Barri
First Telegraphist
Peter Beckman
Second Telegraphist (uncredited)
Allen Russell
Capt. O'Hagan (uncredited)
Fernando Villena
(uncredited)
Robert Rietti
Father Pujardov (voice)
Olive Gregg
Countess Irina Petrovski / Natasha / Miss Jones (voice)
Roger Delgado
Inspector Mirov (voice)