Director Don Coscarelli stumbled on David Wong's novel as a result of an email product recommendation: "True story: I received an email from a robot on Amazon.com, and it told me if I liked the zombie book I just read, that I would like John Dies at the End. I read the little logline, and it was just amazingly strange. I thought, 'Well this might even make a good movie.' Plus, it had arguably the greatest title in motion picture history."
In the book, the location of the town its set it in is never given. Instead, it's usually called "Undisclosed". In the movie, however, the label of the parcel John sends to himself is sent to Sherwood, Illinois. There is no Sherwood, Illinois.
The character of Amy Sullivan in the movie is an amalgam of two characters from the book. In the book, there's an additional female character named Jennifer "Jen" Lopez, who only shares the name with the famous singer. She became Dave's girlfriend and has tried the "Soy Sauce" herself, although she refuses to acknowledge any effects it may or may not have had on her.
The mall where the Mall Of The Dead sequence was filmed is the same mall that producer Roman Perez saw the earlier Don Coscarelli movie Phantasm (1979) at, back when the mall was in business and had a movie theater.
After Dave meets Robert Marley, the boys have a discussion in "Hot-n-Tot Cafe." This name is a play on the word Hottentot, which was how early Europeans referred to the Khoikhoi people of Southwest Africa when they first encountered them in the 17th century. The name Hottentot was given to them by Europeans because of how they thought the language sounded. It is unclear as to why this name was used in the scene. The scene was shot at a real diner with the same name, located at 2347 Pacific Coast Highway in Lomita, CA.
John's full name, John Cheese, is a reference to Cracked.com comedy writer John Cheese (real name Mack Leighty) who co-wrote "John Dies at the End" and the sequel "This Book is Full of Spiders: Seriously, Dude, Don't Touch It" with David Wong (real name Jason Pargin). In the end of "This Book is Full of Spiders," David Wong claims that John demands "at least one scene per book in which he 'ramps something,' along with a flat payment for each time I [Wong] use the name in print."