Though the radiation of a detonated satellite returning from Venus is theorized to be the cause of the dead rising and attacking the living, according to the filmmakers, the actual cause is never determined.
When the zombies are eating the bodies in the burnt-out truck they were actually eating roast ham covered in chocolate sauce. The filmmakers joked that it was so nausea inducing that it was almost a waste of time putting the makeup on the zombies, as they ended up looking pale and sick anyway.
When discussing the film for Bravo's The 100 Scariest Movie Moments (2004) , George A. Romero said that the moment they finished editing the film in Pittsburgh, they put the reels into the cans, threw it into the trunk of the car and drove straight to New York City that night in hopes of having it screen at any willing theater.
Though the cast and crew of the film had nothing but positive things to say about Duane Jones (Ben), Marilyn Eastman (Helen Cooper) would later refer to him as a tortured individual, due to the racial tensions which were still high in the United States during the late sixties. Karl Hardman (Harry Cooper) had become good friends with Jones, and Jones' unfortunate death in 1988 affected him greatly. He would often become emotional when talking about Jones, and believed he received a rotten deal in life due to the nation's racial tensions.
During the filming of the cemetery sequence, shot on two separate days, an unexpected accident caused a fast change of script. The car driven by Barbara and Johnny into the cemetery was actually owned by the mother of Russell Streiner. Unfortunately, sometime between the two filming sequences, someone ran into the car and put a dent in it that would easily be visible on camera. George A. Romero rewrote the scene so the car would come to a stop by crashing into a tree.
One of the original ideas for the script before its many revisions called for Barbara to be a very strong, charismatic character. Instead, George A. Romero and the producers loved Judith O'Dea's portrayal as a catatonic and terrified young girl much better, and edited the script to accommodate the part. Eventually, the idea of Barbara being a strong, central character would be revisited in Tom Savini's 1990 remake of Night of the Living Dead (1990).
One of the working titles for this film was "Night of Anubis". Anubis is the god of embalming/mummifying in the ancient Egyptian (Kemetan) religion. The title was changed once George A. Romero learned that very few understood the reference.
S. William Hinzman based his characteristic saunter (and, subsequently, that of each other zombie) on a film with Boris Karloff, the title of which he could not remember but was most likely The Walking Dead (1936). In that film, Karloff played a man risen from the dead, and walks with a characteristic ungainly saunter.
The Evans City Cemetery was the cemetery used in the original version of the film, but it could not be used for the 30th anniversary edition. Before filming the new footage, a tornado had torn through the Evans City Cemetery, and ironically, it unearthed several graves.
The character of Ben was originally supposed to be a crude but resourceful truck driver, with no specification to race. After Duane Jones, in real-life a self-serious, erudite academic, auditioned for the part, director and co-writer George A. Romero re-wrote the part to fit his performance.
The only real mishap to happen during filming involved producer and actor Russell Streiner's (Johnny's) brother, Gary Streiner. After Duane Jones set the chair on fire, it was Gary's responsibility to extinguish the flames and set the chair ablaze again to preserve continuity, ensuring that smoke would be seen emanating from it near the end of the film. At one point Gary's sleeve caught on fire and, as he ran in terror, S. William Hinzman (in full zombie makeup) tackled him to the ground and helped extinguish the flames, saving him from major injury.
Tom Savini was originally hired by George A. Romero to do the makeup effects for this film. The two were first introduced to each other when Savini auditioned for an acting role in an earlier film that never got off the ground. Romero, remembering that Savini was also a makeup artist (he had brought his makeup portfolio to show to Romero at the audition), called Savini to the set of his horror movie. However, Savini was unable to do the effects because he was called to duty by the US Army to serve as a combat photographer in Vietnam. Savini later appeared in Dawn of the Dead (1978) and directed Night of the Living Dead (1990).
The character of Ben was originally written as an angry person. When Duane Jones was given the role, he expressed concern that the character be rewritten to remove some of the anger - such as the scene where Ben hits Barbara - afraid of how it would be widely perceived in the United States at the time to see a black man acting in this way. The nation was still plagued with high racial tensions during the late sixties; the film was released to theaters shortly after the assassination of Martin Luther King. Nonetheless, George A. Romero and most of the rest of the predominantly white crew decided against it, thinking they were being "hip" by not changing it. Years later, Romero lamented that he had not taken Jones' concerns more into consideration, and thought that he was probably correct. He's expressed that he wishes he could speak with the late Jones again, asking him how he felt about the film's legendary status, and believes Jones would just say "Who knew?" and laugh.
There are two known deleted scenes that were removed at the insistence of distributor Walter Reade Organization. They include a 8-minute expository scene in the basement between Helen and Harry at the bottom of the stairs (which explains the abrupt jump cut shown) as well as a wide shot of numerous zombies covering the landscape, which was replaced with footage of zombies eating near the end of the film. This footage was presumed lost when a flood damaged the storage facility years later at Latent Image, Inc.
The main house did not have a true basement but a dirt potter's cellar, and thus had no long staircase leading down to it. Because of this, the basement scenes were filmed in the editing studio's cellar.
According to the George A. Romero commentary track on the Elite laserdisc and DVD version of the film, the original working print and working elements and materials for the film no longer exist - they were destroyed as a result of a flood that filled the basement where the materials were stored (which was the same basement used in the movie).
At the time of the film's release, any work that did not include a copyright notice was assumed to be public domain. Since the film makers forgot to include this notice, the film slipped into the public domain. It was not until 1 March 1989 that a copyright notice was no longer required.
As Romero explains in "The Directors: The Films of George A. Romero", the day the final editing and voice-over dubbing was complete (4/4/1968), he and John A. Russo literally "threw" the film into the trunk of their car and drove to New York to see if anyone wanted to show it. While driving through New York on the night of April 4th, 1968, Romero and Russo heard news on the radio that Martin Luther King Jr. had been assassinated.
In 2013, a stage adaptation of the film, executive produced by George A. Romero, Russell Streiner, and John A. Russo, debuted in Toronto. The play featured the story of the original film, followed by a series of alternate scenarios.
The film's first scene, the initial cemetery attack on Barbara and Johnny, was the last filmed, in November 1967. The actors had to hold their breath to avoid visible condensation in the frosty autumn air.
The real gravestone that Barbara (Judith O'Dea) cowers beside in the graveyard scene of the movie is that of Nicholas Kramer (1842-1917), whose remains are interred in the Evans City Cemetery in Jackson Township, Butler County, Pennsylvania.
When Ben is nailing wooden boards to the door, small numbers can be seen on them. These were written on the backs of the boards so they could be removed and replaced in between shots, preserving continuity. Some numbers are visible because some of the boards were nailed on backwards.
One of the working titles for this film was "Night of the Flesh Eaters". Originally, the beings attacking the characters were extraterrestrial in origin, either aliens or humans possessed by an alien pathogen, presumably covering a NASA satellite returning from Venus. Eventually, it was decided that the dead would rise and devour the living, presumably due to radiation that was carried by a NASA satellite returning from Venus.
The music used in the film was from a Capitol/EMI Records Hi-Q stock music library, on which the copyright was in the public domain, and cost the filmmakers $1500. It was originally used in Teenagers from Outer Space (1959).
Columbia Pictures was the only major Hollywood studio interested in distributing this film, but eventually passed because it was in black-and-white at a time when movies had to compete with new color televisions. Columbia did distribute the 1990 color remake Night of the Living Dead (1990). American International Pictures (AIP) considered releasing the film, but wanted George A. Romero to shoot an upbeat ending and add more of a love story subplot.
At between 51 and 52 minutes into the film, going by the Elite laserdisc/DVD release, there is a very visible jump cut. The distributors wanted some of the "talky" bits trimmed down, so, about 6 minutes was cut from a basement scene involving the Coopers. The jump is quite clearly visible because at one point Harry is facing one direction and then immediately in the next frame, he is facing another.
The stock music that accompanies Barbara's initial flight from the cemetery zombie was taken from the score for The Hideous Sun Demon (1959), and had been used a year earlier, in the final episode of television's The Fugitive (1963).
George A. Romero was the one operating the camera when S. William Hinzman (the cemetery zombie) attacks Barbara in her car by smashing the window with a rock. When Hinzman shattered the window, the rock barely missed Romero.
George A. Romero chose Evans City Cemetery for the famous first scene due in large part to its isolated location. The crew did not want to be interrupted by onlookers or police inquiring about their presence, and the cemetery being situated atop a hill in a heavily wooded area allowed them the opportunity for privacy. Ironically, it has become a popular tourist attraction and destination for fans of the film in the decades since its release.
The gas pump was not bolted to the ground when the actress who played Barbra, Judith O'Dea, runs into it at the start of the film. She did it with so much force she almost tipped it over on the cameraman.
The Cooper family are partly played by a real family. Karl Hardman (husband Harry Cooper) is the real life father of Kyra Schon (daughter Karen Cooper). However contrary to what is elsewhere reported (and was previously reported here on IMDb) Marilyn Eastman (wife Helen Cooper is not in any way related to either Karl or Kyra.
When applying makeup for the actors playing zombies, Marilyn Eastman focused less on a rotting appearance for most of them (it can still be seen on several, including herself in the "bug-eating" scene), instead concentrating on a prominent facial feature that each actor or actress had and making it appear more prominent for an unsettling image.
There were two trucks used in the film. The first one used in the beginning of the film would not start for the trek-to-the-gas-pump scenes and had to be replaced. Unfortunately, they forgot to break the headlights.
The Chevy truck seen in the new footage is not the same one seen in the original footage. The filmmakers for the new footage were fortunate enough to find a truck owned by a local resident that bore a near-perfect resemblance to the original truck. The owner was kind enough to let them borrow his truck for the film. The owner of the truck was Harold Metz of Zelienople.
During the filming of the new footage for the 30th anniversary edition, actor/composer Scott Vladimir Licina (Reverend John Hicks) suffered a heat stroke in the cemetery and was hospitalized for a few days.
When the movie was in its scripting stage, John A. Russo had developed an idea that was basically described as "teenagers from outer space". This version was not filmed, but the version that was filmed uses stock music from the movie Teenagers from Outer Space (1959).
The trivia items below may give away important plot points.
The matricide scene was accomplished by having Kyra Schon stab repeatedly into a off-screen pillow with a trowel while a member of the effects crew threw chocolate syrup (used as fake blood for a black-and-white film) onto the wall. These scenes were looped with scenes of Marilyn Eastman screaming. The trowel used in the scene was purchased online years later and is now in a private collection.
The social commentary on racism some have seen in this film was never intended (an African-American man holing up in a house with a white woman, a posse of whites shooting a black man in the head without first checking to see if he was a zombie). According to the filmmakers, Duane Jones was simply the best actor for the part of Ben.
Originally, one idea for the script called for Harry Cooper to die from the gunshot wound received from Ben before his daughter became a zombie, which would have resulted in Helen coming down the stairs to find him eating their daughter, rather than the daughter eating him. It was decided that this would probably be far too disturbing and graphic and was changed back to the idea of the daughter becoming a zombie first.
The filmmakers were accused of being "Satanically-inspired" by Christian fundamentalist groups for their portrayal of the undead feeding on flesh and of the Coopers' zombie child (Kyra Schon) attacking her mother (Marilyn Eastman).