The English-dubbed copy of this film is in "public domain" status in the US.
Generally regarded to have kickstarted the Spanish horror film boom of the '70s, due to its box-office success upon release.
This is the fifth in a series of films about the werewolf Waldemar Daninsky.
Released on VHS in the 1980s as both "Blood Moon" and "The Werewolf vs .the Vampire Woman" and was later released on a special edition DVD in 2007 by Deimos Entertainment, a subdivision of BCI Eclipse, as "Werewolf Shadow" (with extras).
Patty Shepard was so convincing as the vampiric Countess it was thought at the time that she might replace Barbara Steele as Europe's reigning horror queen.