Sir Billy Connolly was reportedly very upset that the role required him to shave his beard. He described it as, "ripping out my fuc-king personality."
The pregnancy subplot involving Helen Robinson (Carrie-Anne Moss) was only added because Moss was really pregnant during filming, and they added the pregnancy scenes to keep the continuity throughout the movie as she grew larger.
Sir Billy Connolly accepted the role of Fido in the weeks before filming since he was interested in the acting challenge of making the character compelling without any dialogue.
Stuntman Andrew Dore, set to double for Sir Billy Connolly during the factory scene, died during a cast lunch. This movie is dedicated to his memory.
Timmy's (Kesun Loder's) bedroom contains curtains and a bedspread depicting action scenes from the zombie war.