Director Mario Bava used the mirror-based Schufftan Process to combine live action with miniatures and thereby avoiding the costly matte/optical printing techniques.
This film marks the first collaboration between Mario Bava and his son/assistant director Lamberto Bava. Lamberto would later become a director himself.
This film went through fifteen working titles before American International Pictures settled on "Planet of the Vampires".
German Import DVD has a Super-8 Version (German language only), as a special feature on the disc.
Susan Hart was originally cast as Sanya, but upon arriving in Rome immediately following her honeymoon with AIP co-founder James H. Nicholson, she was locked out of production due to Samuel Z. Arkoff's enforcement of a new anti-nepotism company policy. Hart also suspects that Barry Sullivan's on-set arguments with an unidentified production member was another factor in her dismissal. Norma Bengell was not cast as her replacement until halfway through shooting. Hart would later appear in another Mario Bava film, Dr. Goldfoot and the Girl Bombs (1966), although her only scene in the film was recycled from its prequel, Dr. Goldfoot and the Bikini Machine (1965).
Along with It! The Terror from Beyond Space (1958) and Dark Star (1974), this film is considered to be a primary influence for Alien (1979). Although Ridley Scott would later claim that he had never seen the film before making his, screenwriter Dan O'Bannon explained "I was aware of "Planet of the Vampires", I don't think I had seen it all the way through. I had seen clips from it and it struck me as evocative. It had the curious mixture that you get in these Italian films of spectacularly good production design with an aggressively low budget mentality". Coincidentally, both films also featured special effects devised by Carlo Rambaldi.
Only one spaceship model was built for this film.
Mario Bava worked with a new camera crew on this film.
The costumes for the entire cast were done in only twenty days.
Evi Marandi initially had a more prominent role, but her part was diminished in subsequent rewrites of the script.
Barry Sullivan admitted that while dubbing his lines for the English version of the film, he wept in amazement over its visual quality.
In 1965, American International Pictures distributed this film, dubbed in English and titled "Planet of the Vampires", on a double bill with Monster of Terror (1965).
The original title for this film during production was "Planet of Terror."