- The Other Darrin: Lon Chaney Jr. replaces Boris Karloff as the Monster. Back in the day this was considered as big a deal as when another actor replaced Sean Connery as James Bond.
- Cedric Hardwicke, who plays Ludwig, also appears as Henry Frankenstein, due to the original actor, Colin Clive, having died five years earlier.
- What Could Have Been:
- First draft of the script featured Ygor forming a band of rejects and Wolf von Frankenstein returning.
- Karloff was invited to reprise the role, but declined. Ironically, this film technically depicts the death of his version of the Monster, given that it ends with a new brain being used.
- You Look Familiar:
- The actors who played Lang and Neumüller in the previous film appear in almost same roles (their previous characters being dead and all) in the townhall of Frankenstein. Dwight Frye (Fritz, Karl) is also among the populace there.
- Lionel Atwill, who was Krogh in the previous film, is the ambitious Dr. Bohmer.
Trivia / The Ghost of Frankenstein