The role of Zelda, Rachel's terminally ill sister, was played by a man. Director Mary Lambert wanted Zelda and her scenes to frighten the audience but did not believe that a 13-year old girl was scary so she cast Andrew Hubatsek in the role to make something be "off about Zelda."
Stephen King is a big fan of the Ramones and referenced some of their songs in the novel "Pet Sematary." In homage, The Ramones wrote and performed the theme song "Pet Sematary," which is featured in the film's closing credits. The truck driver was also listening to "Sheena Is A Punk Rocker" by The Ramones.
Mary Lambert tried getting Blaze Berdahl to cry for a scene by suggesting the young actor think back on something from her life that was very sad, but the girl had nothing. Lambert instead ended up offering her more money if she'd cry.
The original screenplay featured the "wendigo" (a Native American demon) that was mentioned in the novel, but it was ultimately cut from the film. Its presence is implied only twice: first, in the scene where Louis is walking through the woods at night and hears something large knock down a tree, and second, when Judd first takes Louis up to the Indian burial ground, there is some kind of loud crash deep in the forest followed by a long, almost feminine howl. Judd says that "it's only a loon," but it is clear that he does not entirely believe it himself.