Revealing: In the scene where Marion's boyfriend and sister visit the Sheriff and his wife at home, there is a camera shot where you can see that living room background scenery ends and there is no ceiling.

Continuity: While in the shower, Marion rubs her right arm with a bar of soap and her hair has yet to get wet. But in the next shot, the soap has disappeared from her hand and most of her hair is wet.

Deliberate "mistake": After being stabbed, Arbogast falls down the stairs in an impossible manner. He is standing tilted backwards all the way down the stairs.

Continuity: When Norman carries Marion's dead body out to the boot of the car, the water on Marion's bonnet changes between shots. In some shots there is water, sometimes there is no water.

Factual error: Janet Leigh is driving from Phoenix, AZ to Bakersfield, CA. On the way there is an interview with a state trooper followed by a shot of a sign on the highway saying, "left lane for Gorman". Gorman, CA is in the general vicinity, but it is not on the route one would take to get from Phoenix to Bakersfield.

Audio problem: When Norman runs down from the Bates house to the motel and meets Marion, he says "Gee, I'm sorry I didn't hear you in all this rain. Go ahead in, please." But you look closely, it looks like Norman is barely moving his lips. In fact it looks like Marion is saying something instead.

Continuity: When Marion gets out of her car at the dealership, she is holding her purse with her hands. But in the next shot, her purse is now around her left arm.

Other: In the scene where Janet Leigh goes to take a shower, she gets into the stall and immediately turns the shower on. What's amazing is that it's the right temperature right as she turns it on. Guess the Bates Motel has really good showers.

Factual error: Norman Bates spies on Marion by removing a picture from a wall in his back office but this cannot be so. If you look at the motel from the outside, Marion's cabin is to the right hand side of the office. As you walk into the office the front desk is on the left (as you can tell when the private investigator arrives) and the back office where Bates has his stuffed birds, etc. is behind the front desk. If he looked through a hole in his back office he would have been looking through an outside wall and not into Marion's cabin, which would be on the other side of the office.