- Deleted Scene: The script contains a scene in which Lisa visits her parents' grave. Unknown to Neville, Lisa is pregnant, and she seeks comfort from her deceased parents before Neville and she leave the city forever. While Lisa is talking to her parents' grave, she hears a sound and investigates a crypt. In it, she spots a female Family member depositing a dead newborn mutant. Lisa can see the mother's grief and empathizes with the woman's loss, despite their being on different sides. Lisa believes that all children, including her unborn baby, will suffer the same fate. Later, Lisa returns to Neville and tells him of the woman in the crypt. Neville asks Lisa if she "took care" of things and Lisa responds that since she may be a grieving parent in a few months, she will not kill a grief-stricken mother. Neville is shocked at first, but then embraces Lisa. While the scene was cut from the final film, the screen credit for "Woman in Cemetery Crypt" remains.
- Disowned Adaptation: Richard Matheson thought the film deviated so much from I Am Legend that it barely counted as an adaptation.
- Referenced by...: The Police's 1981 song "Ωmegaman" is titled after and based on the film.
- Technology Marches On: Whilst it was probably very impressive and advanced at the time, today that infrared scope on the top of Neville's BAR (Browning Automatic Rifle) is absolutely huge.
- What Could Have Been: Charlton Heston asked Orson Welles to direct.
Trivia / The Ωmega Man