Liev Schreiber (Robert Thorn), Julia Stiles (Katherine Thorn), Mia Farrow (Mrs. Baylock), David Thewlis (Keith Jennings), Seamus Davey-Fitzpatrick (Damien), Pete Postlethwaite (Pater Brennan), Reggie Austin (Tom Portman), Michael Gambon (Carl Bugenhagen), Nikki Amuka-Bird (Dr. Becker), Richard Rees (Psychiater Hugh Greer), Janet Henfrey (Mrs. Horton), Giovanni Lombardo Radice (Pater Spiletto), Predrag Bjelac (Vatikanischer Priester der Sternwarte), Massimo Bellinzoni (Subiaco-Mönch), Bohumil Svarc (Papst), Federico Pacifici (Taxifahrer in Rom), Carlo Sabatini (Kardinal Fabretti), Amy Huck (Kindermädchen), Alessandra Vanzi (ältere Nonne)