 Nelson EddyPrince Peter Karagin, aka Peter Teranda | Prince Peter Karagin, aka Peter Teranda |
 Ilona MasseyLydia Marakova | Lydia Marakova |
 Charles RugglesNicki Popoff | Nicki Popoff |
 Frank MorganIvan Danchenoff | Ivan Danchenoff |
 Lionel AtwillProfessor Marakov | Professor Marakov |
 C. Aubrey SmithGeneral Karagin | General Karagin |
 Joyce ComptonMasha | Masha |
 Dalies FrantzDimitri Marakov | Dimitri Marakov |
 Phillip TerryLieutenant Smirnoff | Lieutenant Smirnoff |
 Walter Woolf KingMichael Sibirsky | Michael Sibirsky |
 Frederick WorlockRamensky | Ramensky |
 Abner BibermanLeo Proplinski | Leo Proplinski |
| AArthur W. CernitzSergei Pavloff | Sergei Pavloff |
 Roland VarnoLieutenant Nikitin | Lieutenant Nikitin |
 George TobiasSlaski | Slaski |
 Paul SuttonAnton | Anton |
 Willy CastelloCapt. Testoff | Capt. Testoff |
| PPaul IrvingPrince Morodin | Prince Morodin |
 Mildred ShayJeanette Sibirsky | Jeanette Sibirsky |
 Alma KrugerMrs. Danchenoff | Mrs. Danchenoff |
 Zeffie TilburyNatalya Petrovna | Natalya Petrovna |
| DDemetrius Alexis(uncredited) | (uncredited) |
| DDorothy AtesCafe Girl (uncredited) | Cafe Girl (uncredited) |
| DDouglas BeattieBaritone (uncredited) | Baritone (uncredited) |
 John Bleifer(uncredited) | (uncredited) |
 Charles BrokawSoldier (uncredited) | Soldier (uncredited) |
 Rand BrooksCrying Soldier (uncredited) | Crying Soldier (uncredited) |
 Maurice Cass(uncredited) | (uncredited) |
 Feodor Chaliapin Jr.Soldier (uncredited) | Soldier (uncredited) |
 Irene ColemanCafe Girl (uncredited) | Cafe Girl (uncredited) |
