Writing for The Movie Guide (1992), James Monaco lauded it as a "wonderful horror film...  As reminiscent of House of Wax or Frankenstein as it is of current-day slasher films, I, Madman is a loving salute to the days when movie monsters had hearts." In his book The Gorehound's Guide to Splatter Films of the 1960s and 1970s, Scott Aaron Stine praised the film as an "atypical take on the slasher genre [that] is a reasonably impressive effort."
