In the film version, Sophie's grandfather is no longer her real grandfather (so that no descendant of Christ can be said to have engaged in a sex ritual) and her living grandmother is no longer Saunière's widow. Sophie also looses a brother in the process. The film's ending is robbed of any significance, Sophie is robbed of her own family tree - which happens to be the subject of the book - and her backstory becomes meaningless. Someone ought to break it as gently as possible to Ron Howard that none of us - except maybe clones - would even be on this earth without our ancestors having committed some kind of sex act at one point...

is portrayed in the film as a chump who has obtained false information from Bishop Aringarosa to the effect that Langdon has confessed his crimes to him and presumably intends to kill other people. This is ridiculous on many, many levels such as (1) what motive could Langdon possibly have to kill Saunière and other prominent Priory members? (2) why would he confess his crimes to anybody? (3) why would he confess them to Aringarosa, whom he doesn't know from Adam and who is presumably the only person we can name in the whole film who could possibly profit from those deaths? and (4) why would Aringarosa break his sacred vow of secrecy to denounce a man who is killing off enemies of the Church? Not only is this script-changing lazy, stupid, retarded, ignorant and unjustifiable in and of itself, but we must assume that if it had happened, Fache would be clever enough to see it as the lie that it is.

In the book, Fache is a good-natured and competent soul, with a traditional bent who has actually figured out by himself the link between Aringarosa and Silas (Silas had told the nun in St-Sulpice that he was sent by Aringarosa before meeting and killing her) and is pressuring the latter's sense of guilt for having unleashed Silas on a killing spree to give him more information which eventually disculpates Sophie and Robert Langdon. He is not a member of the Opus Dei and is not a pathologically violent monster.

Equally cut from the film is the elaborate, long-term planning by Teaberg to set up the whole treasure hunt by listening in on all four Priory members with elaborate bugging devices over a period of several months and manipulating Aringarosa.

It turns out in the book that neither the Opus Dei nor the Vatican are villains bent on murder but that they were all manipulated by the evil Teabing for his own end of learning and disseminating the secret. In particular, there is no «secret council» of shady Vatican figures financing the murderous activities of the mysterious «Teacher». In the book, the Vatican is openly intent on dismantling Opus Dei as an embarrassment to the Church and simply paying Aringarosa one of five installments necessary to sever all ties between the two institutions, money which Aringarosa wants to use in part to pay the Teacher in exchange for the Grail secret, with which he intends to blackmail the Vatican into reinstating Opus Dei.