Originally, the script called for the character of Abby to be diabetic, but Panic Room (2002) also featured a little girl with juvenile diabetes, and as it was to be released first, Abby was changed to an asthmatic instead.
Charlize Theron and Stuart Townsend, who play the Jennings, were an actual couple during filming.
Originally, the movie was going to be titled "24 Hours", but the title was changed, to avoid confusion with the FOX television show 24 (2001).