Forrest Tucker as Baron Keller

Eva Bartok as Baron Keller

Marius Goring as Baron Keller

Guy Middleton as Maj. Hobart

Eric Pohlmann as Emile

Arnold Marlé as Prof. Pal Kudnic

Fred Johnson as Chief Agent Farquarson

David King-Wood as Col. Patchway

Reginald Beckwith as Dusty

Guido Lorraine as Franz

Andre Mikhelson as Russian thug answering Ludwigstrasse door

Stanley Zevic as Russian thug #2 at Ludwigstrasse address

Marne Maitland as The phony Kudnic

Arthur Lovegrove as Bert

Derek Prentice as Keller's butler