Son of Frankenstein is a 1939 horror monster film, the third film in Universal Studios' Frankenstein series and the last to feature Boris Karloff as the Monster. It is also the first to feature Bela Lugosi as Ygor. The picture is a sequel to James Whale's Bride of Frankenstein. It is directed by Rowland V. Lee and stars Basil Rathbone, Boris Karloff and Bela Lugosi.
The film was a reaction to the very popular re-releases of Dracula with Lugosi and Frankenstein with Karloff as a double-feature in 1938. Universal's declining horror output was revitalized with the enormously successful Son of Frankenstein, in which the studio cast both Karloff and Lugosi.