A plastic surgeon (Dr. Rossiter), who has just butchered the face of a patient, is on the run. After having an accident and requiring plastic surgery himself, he and his assistants travel to France so the doctor may start anew with a new face and name. After a fatal accident to the owner of a circus, Dr. Rossiter takes over. He soon discovers that he can continue his plastic surgery experiments by operating on murderers, thieves, and prostitutes who all just happen to have some sort of facial deformity or scar. The patients, also with new identities, go to work for the doctor in his circus. The doctor keeps them in line and working through blackmail. As he knows their true identities, they are reluctant to leave. Soon, however, some of the patients become restless and try to 'escape' the doctor. Dr. Rossiter, through a series of 'accidents', makes sure they don't, thereby keeping his secret. Any more of the story would be too much.

Circus of Horrors is a very visually pleasing film. The film's makers appear to have been heavily influenced by the Hammer movies being produced at the time. The lavish colors, costumes, and sets are very Hammer-like. And, like many of the Hammer movies, this one must have been quite shocking for its time. As an example, a knife throwing scene turns particularly nasty.

The movie also features some wonderful acting. Anton Diffring is especially sinister as the mad doctor. Donald Pleasence, in a small role, highlights an above average supporting cast.

The only problem I have with the movie is its tendency to lose focus. Too often, circus scenes seem to go on a little too long and drag the movie down to a snail's pace.