This is one of the upper echelon of Santo films, very well produced, with an excellent cast and solid direction by Federico Curiel, Mexico's most prolific director of vampire films. The inclusion of a "Mad Scientist" in this film adds to the Vampire-Story-Line of the Vampire Women. Despite the title, "The Revenge of The Vampire Women" is not a sequel to the famous "Santo Vs. The Vampire Women" from 1962, the vampire countess here is named "Mayra", which was the name of the character played by Lorena Velasquez in "Attack of The Witches", also co-written by Fernando Oses. This Mayra does mention that the current Santo is the descendent of the man who destroyed her followers after they emigrated to Mexico, but this apparently occurred in the 19th century (although there is no flashback footage), not in 1962 (in Santo Vs. The Vampire Women).  "The Revenge of The Vampire Women" contains some atmospheric photography and makes good use of its sets as we see in the vampire queen Mayra's stake-blood-sequence. Recommended! starring Santo, Gina Romand, and Aldo Monti, Uncut Spanish Version with English Subtitles. 1970 Color 85 Minutes on DVD-R.