Originally Kharis the Mummy, another Universal Classic Monster, was going to be in the film, but he was removed from it due to budgetary restrictions.
According to film historian John Cocchi in "Second Feature", J. Carrol Naish found a hunchbacked homeless man in order to study his walk and gestures. Naish paid all of the man's expenses during this time.
The names of the three German villages that appear in Universal's Frankenstein series are rather confusing, to say the least. Frankenstein (1931), Bride of Frankenstein (1935), and Son of Frankenstein (1939), all take place in or near the village of Frankenstein. In The Ghost of Frankenstein (1942), Frankenstein's Monster and Ygor travel from Frankenstein to the village of Vasaria, where both that film and Frankenstein Meets the Wolf Man (1943) take place. However - in a geographic disconnect - in this film the Monster and the Wolf Man are both found frozen in ice near the village of Frankenstein. They are then both revived by Dr. Gustav Niemann and Daniel and, together, all four of them move on to the village of Visaria.
The sequence in which the shadow of Dracula transforms into a bat was directed by Universal Pictures' resident animation maven Walter Lantz, who also created the studio's most popular animated cartoon star, Woody Woodpecker.
Bela Lugosi was intended to play Dracula in this film, but his role in it was dependent on the presence of Boris Karloff being released from the stage tour of the play Arsenic and Old Lace (1944). Shooting was delayed as a result and John Carradine was finally cast as Dracula instead of Lugosi, who had a prior engagement: ironically, playing Karloff's role of Jonathan Brewster in another touring company of "Arsenic and Old Lace."