In Stephen King's novel, Judd mentions that a dog went wild in a nearby town and killed several people. This is a reference to the events of Cujo (1983), another novel by King. It is common for characters in King's novels to mention the events of his other novels.
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.
(At around nine minutes into the film) Louis claims his cat, Church, is named after former British Prime Minister Winston Churchill. Seven blue British Shorthair cats were acquired to play Church, and each of them were trained to do a specific action for the camera.
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.
The idea for this story came about when Stephen King's daughter's cat, Smuckey, was killed on the highway outside their home. Smuckey's name appears on gravestones in the pet cemetery, in both the film and the novel.
Over the years critics have frequently voiced concern over the impression that being in this film must have left on young Miko Hughes. On the contrary, his parts during the horror sequences were shot separate from the more "disturbing" elements and violent action. He was later edited into these scenes, while a child-dummy was used during the more intense action footage.
The scene where Pascow first visits Louis in the night was originally shot with star Dale Midkiff clad only in jockey shorts (as Louis is described in the novel). However, the scene was later reshot with Midkiff wearing full pajamas. The filmmakers were concerned that Midkiff's attractive physical appearance would diminish the eerieness of the scene.
The original cut of the film delivered to Paramount's executives was judged to be too long, so excess footage had to be removed. They also decided that the closing scene was too tame and at their request it was re-shot to be more graphic.
Initially, Paramount executives wanted a pair of twins to play the role of Gage, like those chosen to play Ellie, which was the more cost-effective option. However, Lambert was very impressed with three-year old Miko Hughes, whom she felt was a natural talent despite his young age, so she lobbied the studio to accept her choice.
Pet Sematary was director Mary Lambert's second feature film. She was better known for her work directing music videos, especially those for Madonna including "Like a Prayer" and "Material Girl". Through her work in the music industry Lambert was friends with The Ramones, who were one of Stephen King's favorite bands. She approached them about recording a song for the film and they agreed to write and perform Pet Sematary, which is featured in the closing credits.
During the opening credits, there are several children's voices reciting epitaphs for deceased pets. One of these voices belongs to Jonathan Brandis, who starred as the young Bill Denbrough in another of King's most popular works, It (1990).
Other filming locations included an abandoned granite quarry on Mount Desert Island in Acadia National Park, where the burial ground was constructed, a forest near Ellsworth for the pet sematary, and Mount Hope Cemetery in Bangor for the graveyard scenes.
The trivia items below may give away important plot points.
The role of Zelda, Rachel's dying 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."
The story was inspired by actual events experienced by Stephen King that occurred while he was living in Orington, Maine with his family. King recalled that while living there, his daughter's cat was killed on the highway. Much of Ellie Creed's emotional outburst was taken directly from King's own grief-stricken daughter. King also remembered that once, his youngest son had nearly run into the road while a truck was speeding down it, much like Gage does in the film. The character of Judd Crandall was based on the elderly neighbor that lived across the road from King. Also, there was an actual pet cemetery in the woods behind the King house, which became the basis for the one in the novel.
Judd Crandall's house for the film was actually a facade built upon a smaller preexisting house. For the finale, where the house is burned, an asbestos shield was constructed between the two houses so that while burning the facade no damage would occur to the smaller house it was built upon.
The picture at Rachel's parents' house is a painting of Zelda as a child, before her spinal meningitis. Gage is later seen wearing a similar outfit (as well as having her red hair) to signify that Zelda has come back through him, which was Rachel's deepest fear.
The character of Missy is actually the blending of two characters into one. In the book Missy does not commit suicide. The only characters to die prior to Gage's death are Pascow and Norma Crandall, Jud's wife.
The storyline revolves on the omen of being hit by the fast trucks on the road. Stephen King would himself suffer a similar accident in 1999, when he was struck by a minivan while walking on the shoulder of Route 5, in Lovell, Maine.
At 59:09, as the house goes up in flames, Timmy Baterman shouts " love dead, hate living". This is line originally from 'Bride of Frankenstein', as spoken by Boris Karloff as the Monster. Timmy repeats the line a minute or so later.