During pre-production, Robert Downey Jr. set up an office next to Jon Faverau, so they could collaborate on the character of Tony Stark.
Paul Bettany, who voiced Tony Stark's A.I. assistant, 'JARVIS', in the film, recorded all of his lines and dialogue in only two hours.
2008's 'Iron Man' is Marvel Studio's first self-financed film.
The film was shot in California, on the West Coast, because Director Jon Favreau felt that too many superhero films were shot on the East Coast, specifically New York City.
A cameo of 'Captain America's Shield' appears during the scene where Tony Stark is having his armor removed, 01:21:54 into the film.
The armor that Tony Stark creates in the caves during his imprisonment, designated the 'Mark I', actually weighed approximately 90 pounds.
Robert Downey Jr. spent five days a week, weight training and practicing martial arts to prepare for his role in 'Iron Man'.
Rachel McAdams was originally intended to play 'Pepper Potts', Gwyneth Paltrow's role.