This is the first movie in which, as in the novel, Dracula begins as an old man and becomes younger as he feeds.
On a documentary included on the DVD, Director Jesús Franco claims that Klaus Kinski ate real flies as Renfield instead of fake ones.
Sir Christopher Lee (Count Dracula) and Herbert Lom (Dr. Van Helsing) never saw each other during filming. They shot all of their joint scenes separately.
Sir Christopher Lee was reportedly tired of playing Count Dracula, and was convinced to join the cast only after being promised that this movie would be a faithful adaptation of Bram Stoker's Dracula novel, but the screenplay ultimately made numerous and significant changes to the story. According to director Jesus Franco though, he and Lee remained good friends for years.
Director Jesús Franco's first choice for the role of Dr. Abraham Van Helsing was Vincent Price. He was not able to obtain Price, due to his exclusive contract with American International Pictures, and second choice Dennis Price was forced to withdraw because of illness. Franco was able to get his third choice, Herbert Lom, for the role.