Continuity mistake: After Vittoria sees the little spot of blood on her chin she wipes it all off with her finger, but a moment later a good bit of the spot is still there. (00:08:30)
Factual error: Langdon says Air Water Fire and Earth are fundamental scientific elements. That's not true. The "five elements" are philosophic, not scientific. (00:20:25)
Continuity mistake: When the new threat is shown to Professor Langdon, the first time he asked it to be stopped, the threat says "We will brand your preferiti and sacrifi-" it end there. But when it was played again two minutes later, it repeated to "and sacrifice them to the altars of Science." (00:20:50 - 00:22:15)
Character mistake: While examining "Diagramma della Verita" in the Vatican archives, Langdon is careful to use a cotton glove and a pair of tongs to turn the pages. But when he returns later to search the Bernini texts for clues about the "fire" church, he turns the book pages with his bare hands. (00:36:30 - 01:04:55)
Visible crew/equipment: In their first visit to the Vatican Archives, Robert and Vittoria are sitting at the table across from one another. When Vittoria asks Robert "Do you need help with Latin?" the shadow of the boom mic is seen moving on Robert's face. (00:37:45)
Continuity mistake: When Landon and the Vatican Police arrive at the Piazza del Popolo at 7:59pm when looking for the first victim, the overhead shot shows shadows cast by their car and tourists in the area are at a very shallow angle (shadows 3 - 4 times the length of the height of objects casting them), indicating that it's late in the day. However, the shots from ground level show shadows cast at much steeper angles (only about 1/2 - 3/4 of the length of the object height), indicating that it's much closer to noon. (00:46:35)
Visible crew/equipment: In St. Peters Square at 8:58pm the head of the Saints statue looks like Director Ron Howard. (00:57:25)
Continuity mistake: During one of the news reports outside St. Peter's Square, the news reporter's left hand moves from out in front of him to down to his side. (01:01:40)
Factual error: At 1:37:15 the message received on the laptop instructs the villain to find his final payment in the Volkswagen located "N/E corner Via Giulia." When he flees Langdon he does so on the Passetto which runs east toward the Vatican, and he scales off the wall a short time/distance later to find the car. Via Giulia is actually south and across the Tiber river from the Castel Sant'Angelo. The villian would never have reached Via Giulia going on the Passetto or in that amount of time. (01:37:15)
Revealing mistake: Following the drowning cardinal scene, Richter is shown loading a pistol with a magazine and chambering a round. You can immediately hear the hammer striking the firing pin on the pistol, revealing the gun was empty. As well as Commander Richter's pitiful trigger discipline. (01:40:30)
Continuity mistake: When the antimatter explodes in the helicopter, the the shock-wave blasts off part of the roof inside St. Peter's Basilica, above the alter, obliterating everything below. However, in the scene where the Camerlengo self immolates himself at the altar close to the end of the movie, there is no evidence of the shock wave earlier, the candles are burning, oil lamps are lit and alter is intact. (01:54:10 - 02:07:40)
Character mistake: The reporter speaking Spanish at the end of the movie spells the Spanish word for fire wrong. He says "inciendo" instead of the correct "incendio." (02:07:11)
Factual error: Contrary to what the movie states, priests can be elected Pope - they are simply elevated to the rank of Bishop before taking the office.
Suggested correction: Him being only a priest was simply an excuse not to elect him. Those who did not want him to be pope were trying to find any reason to keep it from happening.
Any baptized Catholic male can be elected pope, although it has only happened once. Pope John XIX in the 11th century was a layman, ordained after his election.
Other mistake: After Langdon saves the last of the Preferati by diving into the fountain, he heads off to St. Angelo with dry clothes. Since it is only ten or fifteen minutes later, his clothes should be soaked.
Factual error: In the scene where Vetra is taken to examine the body of the deceased pope, the corpse is exposed after the marble slab and the lid of the casket is removed. In reality, papal funerary protocol requires the body to be triple-sealed. It is first placed in a coffin of cypress wood (to symbolise humility), and is then hermetically sealed in a zinc coffin to slow down decomposition. Finally, the zinc coffin is then placed inside of an oak coffin before being interred beneath the marble slab.
Factual error: When Langdon arrives at piazza del Popolo and drives over the square, the church (Santa Maria del Popolo) is at his left side. But in real Rome, the church is at the right side.
Factual error: The Fontana dei Quattro Fiumi, where the fourth cardinal is taken to be executed, is nowhere near as deep as it's depicted in the film. In reality it's only little more than a foot deep.
Factual error: The College of Cardinals debate whether or not to allow Father McKenna into the papal election as a candidate via election by acclamation. That process of election was abolished by Pope John Paul II in 1996; the secret ballot method is the only legal means of electing a Pope.
Factual error: In the scenes in Piazza Navona where the fourth Bishop is nearly drowned in the Fountain of the Four Rivers, the fountain is easily approached by car and on foot without any barriers. The real fountain has a railing around it of stone posts connected by long, oval-shaped iron rings and bars.
Revealing mistake: When Langdon and Victoria walk towards the Pantheon, the first two angles show them walking alone with some stunt-women behind. But in the third angle, a couple of seconds later, a huge line of people appears, lining perfectly in the back, watching the camera. Obviously a group of real tourists standing behind a security line watching the shooting.