Despite the film's overall slapstick tone, the monsters are intentionally not depicted comically, and retain a considerable amount of their original menace.
Suggested MPAA rating (if ratings had been available in 1948): PG-13 or even R due to intense/terrifying scenes and violence.
It's a comedy but a few scenes may be frightening for some very young kids.
The scene where Talbot transforms into a wolf at the beginning and starts tearing up his apartment, the vampire bat changing into Dracula, and Dracula and the monster coming out of their coffins.