The film's director, David Cronenberg, has a cameo in this film as the doctor who helps Ronnie deliver her maggot baby.

Tim Burton was offered the chance to direct.

Michael Keaton was the first choice for Seth Brundle.

At least 20 different versions of the 'space bug' (Brundle's final mutated form) were produced, many of them bearing a mostly symmetrical design so as to facilitate the building and operating of animatronics and puppets. One by one they were duly turned down until the special effects department finally in frustration came up with a totally unfeasible asymmetrical look that would take months to construct and be an absolute nightmare to work on set. The producers loved it from the first sight and that's what appears in the final film.

An extended ending showed Geena Davis dream about giving birth to a baby with butterfly wings. This was cut from the film to emphasize the drama of Seth's death.