* ActingForTwo: TheMusical originally had Fred Applegate play both Inspector Kemp and Harold, the blind Hermit.
* FakeNationality: In ascending order: Inga, Frau Blücher ([[RunningGag *WHINNY*!]]) and Inspector Kemp.
* HeyItsThatGuy: Herr Falkstein was the last film role played by beloved character actor Richard Haydn, who was (among many other parts) Uncle Max in ''Theatre/TheSoundOfMusic'' and the Caterpillar in ''Disney/AliceInWonderland''.
** Tell anyone who hasn't seen the film that Gene Hackman is the blind hermit and they won't believe you.
** Roger Bart, the original Carmen Ghia (and later one of the follow-up Leo Bloom actors) from TheMusical version of ''Film/TheProducers'' is Frederick in TheMusical version of ''Young Frankenstein''.
** Andrea Martin of ''Series/{{SCTV}}'' fame is Frau Blücher (*WHINNY*!) and vamps up the role in TheMusical for the song "He Vas My Boyfriend."
** Broadway actress Sutton Foster takes the Inga role in TheMusical, and would later do ''Film/ThoroughlyModernMillie'' and ''Theatre/AnythingGoes'' for Broadway too.
** Many younger viewers should recognize the monster, played by Peter Boyle, as [[Series/EverybodyLovesRaymond Frank Barone.]]
** Lesser-known example: the sadistic jailer who mashes the Monster's BerserkButton one time too many (scaring him with lit matches) is Oscar Beregi, who played the sadistic Nazi who receives a suitably [[DrivenToMadness karmic punishment]] in the ''TwilightZone'' episode "Death's-Head Revisited".
** In a deleted scene, [[Series/HogansHeroes General Burkhalter]] reads the old Baron's will.
** The old man in Dr Frankenstein's demonstration at the start of the film is the Reverend in BlazingSaddles.
* ThrowItIn
** Igor's hump, which changes position from scene to scene; Marty Feldman decided to do this on his own, without telling anybody beforehand. When someone finally noticed, they added a bit where Frederick does as well.
*** This has appeared again in other Mel Brooks films - Prince John does it with his facial mole in ''RobinHoodMenInTights''.
** During a search in the forest, Inspector Kemp's wooden arm appears to have switched sides. On closer inspection, it's actually the entire scene that's obviously been flipped as his eyepatch and monocle are on the other eye, and his badge is on the other side.
** Brooks ad-libbed the sound of a cat getting hit with one of Frederick's darts.
** Almost a Throw It ''Out'' moment; in some interviews, Mel Brooks stated that the only point during production where he and co-writer Gene Wilder seriously disagreed was the inclusion of the "Puttin' On the Ritz" number. Gene loved the idea but Mel hated it. After Gene vehemently defended the scene, Mel decided, "If you feel that strongly about it, we'll shoot the scene. If it works, we'll use it, if not, we won't." They shot it and it became one of the highlights of the movie.
*** The monster's shout of "PUTTINAHNDARIZZZ!" was Peter Boyle's idea.
*** Wilder wrote in his autobiography that he kept trying to find ways to add additional scenes to the shooting schedule because the cast had a thoroughly great time together and Wilder didn't want filming to end.
** The bit where Frederick accidentally stabs himself with a scalpel wasn't in the script--Gene Wilder accidentally did that for real. ''[[AwesomeMoments And kept going.]]''
* ContinuityNod: A lot of the laboratory equipment were Kenneth Strickfadens original props from the 1931 Frankenstein.
* The {{Aerosmith}} song 'Walk This Way' is named after Igor's cane gag.