Revealing: When Marion is driving her car through the night, she keeps looking at her speedometer. You can clearly see that the gear shift lever is in "park" as she is driving.

Visible crew/equipment: While Janet Leigh is being stabbed to death by Mother, as Janet turns around in the shower, it is possible to see part of the moleskin that Janet wore for the scene for a split second.

Deliberate "mistake": When Norman picks up Marion's body to carry it to his trunk, a bra is visible through the shower curtain. Gus Van Sant included this goof in his 1998 remake.

Factual error: When Janet Leigh is shown lying dead on the floor of the shower, there is a close-up of her open eye. The pupil is contracted to a pinpoint (obviously due to the bright lighting) where it should have been dilated. After the film was released, Hitchcock heard from several ophthalmologists who pointed this out and suggested he use belladonna eyedrops in the eyes of "dead" people in future films, as the chemical prevents the pupils from contracting.

Continuity: When Marion and Norman are talking after he has brought in some sandwiches, Marion tears the same piece of bread 3 times on different occasions.

Revealing: After Marion has been murdered there is a close-up of her face. If you look down to her neck you can see her pulse.

Visible crew/equipment: When Marion arrives at the car dealership, the salesman sees her and starts walking towards her. If you look carefully, there is a wire trailing out his trouser leg, most likely for a hidden mic.

Continuity: When Marion steps into the shower, we can hear (not see) her unwrap a bar of soap and throw the wrapper on the floor of the shower. But when Norman is cleaning the bathtub, after Marion is killed, the wrapper is no where in sight.

Continuity: When Marion arrives at the Bates motel, she sounds the car horn for the first time, the windscreen wipers are switched on. She gets out of the car, looks towards the old house, then goes back to the car, as she sounds the horn for the second time the windscreen wipers are now switched off.

Visible crew/equipment: When Marion first gets ready to get in the shower, the camera is panning back over the bed to show the newspaper with the cash wrapped up in it.  As the camera pans back, one can clearly see the camera's shadow on the bed as it pans back.

Visible crew/equipment: After Marion's sister and boyfriend look through the Number 1 bathroom and find the ring on the toilet, they turn off the light. On the wall behind them you can make out a square beam of light, but no other lights are on in the cabin.

Other: In the shower scene, Marion Crane's palm looks water wrinkled as if she's been in the shower for quite a long time even though she was only in for a few moments before Norman stabs her. Also, when Norman drags her out of the bathroom, Marion's legs are stiff and together and she has her toes pointed.

Continuity: As the camera zooms into the hotel window, you can see a shadow on the blinds. But in the next shot, the shadow is now longer (even though it's supposed to be in real time).

Continuity: When Marion steps into the shower and pulls the curtain shut, if you look closely, you can see a rubber bath mat with holes in it. After this shot, the mat is not seen again (during the murder or the clean-up).

Continuity: Norman brings a tray of food to Marion, when she says "So long as you've fixed supper we may as well eat it," watch how her folded arms change position from hands tucked underneath, to hands on top of her arms.

Continuity: After seeing Marion's dead body in the bathroom, Norman accidentally knocks down a framed picture of a bird (with the picture facing up and it is a few inches away from the wall). But when Norman is spreading the shower curtain on the floor, the picture has changed position (with the picture now facing down and it is against the wall).

Continuity: In the scene after Janet Leigh is killed Norman goes into Cabin one and starts mopping. He puts the mop in front of the bed for a second. Through the mirror you can see the mop fall when he put it down, but when he goes back to get it, the mop is up again.

Continuity: When Marion is buying another car at the dealership, in the background you can see the same extras walking in different directions on the sidewalk.

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.