The original cut of the film ran for nearly 2 hours and 45 minutes. As of 2021, this version has never been screened publicly and was once considered to be lost until it was rediscovered through the efforts of Romero scholar Kevin Kriess and the Living Dead Museum.
Romero's original script for the film had the character of Martin as an older person who was actually established as a vampire struggling to live in a modern world. However, when Romero saw John Amplas' performance on stage he re-wrote the character with Amplas in mind, making Martin a younger and more innocent character.
According to producer Richard P. Rubinstein on the Dawn of the Dead (1978) audio commentary track (on its Ultimate Edition DVD version), by the time both he and George A. Romero got together to make this film, Romero was in serious debt (almost 1 million dollars) after the back-to-back failures of the films that he'd made after Night of the Living Dead (1968). Rubinstein told Romero that it was all right to declare bankruptcy and start over again; however, Romero refused because he felt it was inappropriate to back out on the people who had helped invest in his films. Rubinstein, having a lot of respect for Romero for not walking out on these people, partnered up with him so he could help him get out of debt. This was their first film together but it wasn't until they made Dawn of the Dead (1978), which became a financial success, that they were able to pay back Romero's debts.
Director George A. Romero originally wanted the entire film to be in black and white, but the producers didn't want to risk this experiment and insisted that the majority of the film be in color.