Revealing mistake: At the end of the telephone conversation between Krendler and Verger we see Krendler with his mobile phone, and through Krendler's phone we hear Verger hanging up. The sound we hear is unequivocally that of a receiver being hung up on a desktop telephone, but in all of the shots portraying Verger in this sequence we see him using a mobile phone. With mobile phones a conversation is ended simply by pressing a button-there is nothing to hang up. (01:21:20)
Continuity mistake: While Hannibal narrates what Clarice is reading on his letter, Hannibal concludes by saying, "I imagine you sitting in a dark basement room, bent over papers and computer screens. Is that accurate? Please tell me truly, Special Agent Starling. Your old pal, Hannibal Lecter, M.D." But on the letter's second page he writes, "... 200 hawk, one wiring hanging down. Is that fairly accurate? Tell me truly, Special Agent Starling. Regards, Hannibal Lecter, M.D." (00:35:20)
Factual error: When Clarice is being questioned about the fake postcard, they are supposed to be in Washington DC, but the James Monroe building located in Richmond, Virginia can be seen through the window. (01:24:56)
Continuity mistake: During the brains-for-dinner scene, Clarice sneaks her knife under the table to use against Lecter. A few lines of dialogue and camera angles later, the knife is back on the table, and Clarice sneaks it under the table - again.
Continuity mistake: In the scene where Clarice wakes up in Krendler's house heavily drugged, she looks at her things on the chest outside of the room. Her denim jacket is there. However, we see her take this off and leave it in her car when she decides to go in to the Verger barn.
Revealing mistake: When Pazzi is killed, there's a shot of his cell phone and phone battery slamming into the ground followed by a splatter of his innards. However, there is a (rather obvious and poorly timed) jump-cut in the middle of the shot, right before his innards splatter down from above. His cell phone is still moving about a bit, when suddenly it goes perfect still in an unnatural way. It also moves ever-so-slightly to the left when the cut happens. It's supposed to appear to be one continuous shot, but it's clear they dropped the cell-phone, waited for it to settle, then dropped the innards and tried to edit it so the shot moved faster.