Factual error: When Vittoria shows Kohler and Langdon the underground lab, she searches for the dial tone on her cellphone (and fails as they are underground), thrice. Cellphones don't have dial tones.

Factual error: At the end of the book (spoiler alert) the cardinal, Mortati, states that the pope did not sin when he had a child with Maria via artificial insemination. For the Catholic church, this is false. The church condemns unnatural sexual acts between two persons, one of the most unnatural being artificial insemination. The idea that the pope's "devil's advocate" would allow this behavior is absurd.

Factual error: Maximilian Kohler makes a point of Copernicus (along with many other scientists) being murdered by the church for revealing scientific proof that contradicted the church. However Copernicus actually died from a stroke.

Factual error: In one of his lectures Robert Langdon tells his students that the Christians got their tradition of communion, eating their god, from the Aztecs. The Aztec civilization dates to the 13th century while the tradition of communion is as old as Christianity itself. And even disregarding when the Aztecs lived, the Europeans had no contact with America until the late 15th century and could thus not have gotten any traditions that way.

Factual error: Robert Langdon insists that Harvard astronomer Edwin Hubble proposed the theory of the Big Bang. Hubble never was associated with Harvard.