Frankenstein's unscrupulous colleague, Dr. Bohmer, plans to transplant Ygor's brain so he can rule the world using the monster's body, but the plan goes sour when he turns malevolent and goes on a rampage.
| Production | George Waggner | Producer |
| Directing | Erle C. Kenton | Director |
| Writing | Scott Darling | Screenplay |
| Art | Russell A. Gausman | Set Decoration |
| Editing | Ted J. Kent | Editor |
| Camera | Elwood Bredell | Director of Photography |
| Costume & Make-Up | Ellis Burman | Makeup Artist |
| Costume & Make-Up | Vera West | Costume Design |
| Camera | Milton Krasner | Director of Photography |
| Costume & Make-Up | Jack Pierce | Makeup Artist |
| Sound | Hans J. Salter | Original Music Composer |
| Writing | Mary Shelley | Characters |
| Sound | Charles Carroll | Sound |
| Sound | Bernard B. Brown | Sound Director |
| Writing | Eric Taylor | Original Story |
| Directing | Charles S. Gould | Assistant Director |
| Crew | John P. Fulton | Special Effects |
| Crew | Eddie Parker | Stunts |
| Sound | Charles Maxwell | Orchestrator |
| Sound | Charles Previn | Music |
| Art | Harold H. MacArthur | Art Direction |
| Art | Jack Otterson | Art Direction |
