A Neanderthal man is lynched by villagers and Count Frankenstein brings the monster back to life.

[2] Among the different hypotheses of who directed the film included Spanish actor Ramiro Olvieros and producer Oscar Brazzi, cinematographer Mario Mancini, producer Dick Randall and screenwriter William Rose.

[2] The Italian copyright agency SIAE certified that director Robert H. Oliver was a pseudonym of Mancini.

[3] Frankenstein's Castle of Freaks was distributed theatrically in Italy by Nettunia Film on 19 February 1974.

[2] Curti described the film as having a minor cult status in the United States when it aired on Elvira's Movie Macabre in the 1980s.