In 2007, this movie was selected for preservation by the BFI, but it wasn't until 2011 that an extended print, including a longer version of the disintegration sequence, was discovered at the National Film center in Tokyo.
Sir Christopher Lee (Dracula) has only sixteen lines in the entire film, all dispensed by the 10 minute mark.
Peter Cushing did the stunt where he leaps over a banister himself. He insisted on doing so, against the studio's concerns that he might injure himself.
In the U.S., the title was changed to "Horror of Dracula" to avoid confusion with the classic (Dracula (1931)). This was a real concern since the Bela Lugosi version was still being booked into theaters (through Realart) until the Shock Theatre package of classic Universal horror movies was released to television.
The cape worn by Sir Christopher Lee was discovered in 2007 in a London costume shop during its annual inventory-taking. It had been missing for thirty years and is believed to be worth around $50,000. Lee was contacted to verify its authenticity.