The scene in which Nell is given a pair of red Doc Marten boots stemmed from the fact that the insurance company refused to cover Ashley Bell for her exorcism scenes if she was running around barefoot.
The film's poster was banned in the UK after receiving complaints deeming the image offensive.
A crew member's brother was a real exorcist, and was on set advising director Daniel Stamm. He makes an unbilled cameo in the film and can be seen to the left of Reverend Cotton Marcus when he delivers his sermon about the Prince of Lies.
Shot in Louisiana partly because of a generous tax credit.