Leslie Howard
— Stephen 'Steve' Locke
Kay Francis
— Elena Moura
William Gargan
— Bob Medill
Phillip Reed
— Gaston LeFarge
Irving Pichel
— Sergei Pavlov
Ivan F. Simpson
— 'Poohbah' Evans
Halliwell Hobbes
— Sir Walter Carrister
J. Carrol Naish
— Commissioner of War Trotsky
Walter Byron
— Under Secretary Stanley
Cesar Romero
— Tito Del Val
Arthur Aylesworth
— Mr. Henry Farmer
Alphonse Ethier
— Paul DeVigney
Frank Reicher
— Mr. X
Tenen Holtz
— Lenin
Doris Lloyd
— Lady Carrister
Mary Forbes
— Lady Catherine Trehearne
Marina Koshetz
— Maria Nikolaievna (as Marina Schubert)
George C. Pearce
— Lloyd George (as George Pearce)
Gregory Gaye
— Mr. Kolinoff
Paul Porcasi
— Count Romano
Glen Cavender
— Russian Policeman (uncredited)
Claire McDowell
— Woman Saying 'Lenin will Live' (uncredited)