In one scene, Leonard quickly passes in front of a comic book store. The Batman logo is displayed prominently on the store's window. Christopher Nolan later directed Batman Begins (2005) and The Dark Knight (2008).
Before Carrie-Anne Moss was cast as Natalie, Ashley Judd, Famke Janssen and Angelina Jolie were considered to play the role.
Stephen Tobolowsky has stated that during his audition for Sammy, he had mentioned to Director Christopher Nolan that he had experienced amnesia personally. A few years earlier, he was given an experimental pain killer that induced amnesia for a surgery he had undergone. Tobolowsky said it may have helped him get the part because no other actor would likely have had his first hand experience.
This is the only Christopher Nolan-directed adaptation in which Nolan has sole writing credit for the screenplay.
In the reversed opening scene, the footage of the shell casing reversing is really writer/director Christopher Nolan blowing on it, since it would have been too difficult to try to get the shell casing in a close-up view as it hit the ground, while keeping the camera still. In order to get a better looking scene in reverse, they didn't simply film it forward and reverse it in editing. They actually fed the film through in reverse, making a crisper picture. However, this specific shot was not meant to be filmed in reverse. It was done accidentally, and so they had to, in editing, reverse it. That means it's a shot of a simulated reversal, recorded backwards, and then manually reversed to get the desired effect.
Aaron Eckhart, Brad Pitt, Charlie Sheen and Thomas Jane were considered for the role of Leonard before Guy Pearce got the part.
Chronology: When numbering the scenes chronologically, then sorting them how they appear in the film, the pattern becomes more clear. The letters A-V will represent the color scenes (with A happening chronologically first, and V chronologically last), and the numbers 1-22 represent the black and white scenes chronologically. The scenes appear in the film like this: 1, V, 2, U, 3, T, 4, S, 5, R, 6, Q...20, C, 21, B, 22/A The two types of scenes alternate. The black and white scenes (numbers) start from the very beginning soon after the injury, and work forward to the climax at 22/A, while the color scenes (letters) work backward from the climax at 22/A. The climax scene (22/A) changes to color halfway through, showing the convergence of the two story lines.
"Paranoid Android" by Radiohead was originally going to be used in the closing credits, but Christopher Nolan decided that the royalties needed to use this song (owned by Capitol Records) would be too great for this low-budget film.
Although the opening scene is literally shown backwards every single sound effect is in fact a "normal" forward-played sound effect. The only sound played backwards is Teddy screaming, "No!"
Christopher Nolan's screenplay was based on his brother Jonathan Nolan's story "Memento Mori". But the screenplay is still considered original (rather than adapted) because Jonathan's story wasn't published until after the film was completed.
The camera that Leonard Shelby used to film is a Polaroid 690.
The medical condition experienced by Leonard in this film is a real condition called Anterograde Amnesia - the inability to form new memories after damage to the hippocampus. During the 1950s, doctors treated some forms of epilepsy by removing parts of the temporal lobe, resulting in the same memory problems.
The white Honda Civic parked next to Leonard Shelby's Jaguar is Christopher Nolan's car.
The film took a total of 25 days to shoot.
The tattoo parlor is named after Emma Thomas in the movie, which is Christopher Nolan's wife.
Christopher Nolan's first pick for the role of Leonard was Alec Baldwin
Based upon the short story 'Memento Mori' by Jonathan Nolan - the brother of director Christopher Nolan.