While Phoebe is looking at herself in the mirror during the final scene, a crew member sitting on a crane is visible for a few seconds at the top of the shot.
When Karen, Bill and Margo are returning from a long weekend in the country, they run out of gas. They mention having driven the car over the last few days, but in the two closeups of the dashboard the odometer only reads between 00023 and 00024 miles - the studio probably bought a new car and cut it apart for the interior process shots.
After Margo reads the note written by Eve, Bill says, "I understand she's now the understudy in there." However, when he turns his head to the camera, his lips aren't forming any words.
When the car runs out of gas, the fuel gauge still shows that the tank is just under half full.
In the first scene just as the camera pulls away from the award plaque, the dolly tracks are visible on the floor.
The hands in the bedside clocks do not move.
About 45 minutes into the film, Margo and Bill are having an argument about Eve before his birthday party. Margo angrily folds her arms across her chest and her diamond bracelet clasp breaks and dangles against her dress. It isn't part of the story. It is fixed in the next frame.
In the Cub room, after Eve has returned from her restroom talk with Karen, Addison DeWitt is tapping his cigarette into the ashtray. The cigarette falls off from the holder. He continues tapping until he realizes it fell off and then he attempts to hide the holder behind his hands.
In the closing credits, the character of Bill Sampson is shown as Bill Simpson.
After she drinks the martinis, Margo goes up the stairs holding the cigarette in her right hand. Next shot it is in her left hand.
In The Cub Room, Margo holds a lit cigarette. In the next shot, without having put it in her mouth, she puffs a cloud of smoke.
After Bill proposes a toast to Margo, she changes the cigarette from her left hand to her right, but in the next shot it is still in her left hand.
After she arrives at home, Eve picks up one ice cube, puts it in the glass and pours a drink. Phoebe startles her and she drops the drink. Phoebe gathers the glass and two ice cubes.
When Addison slaps Eve in the hotel room, her head snaps toward him rather than away, indicating a "stage" slap.
When Eve and Addison De Witt are walking down the street in New Haven from the Schubert Theater, the pedestrians behind them are walking at a faster pace, but never gain any ground on them. This is because "back projection" is being used; George Sanders and Anne Baxter are not really walking down a street. They are "walking in place" and the background is actually projected film being shown behind them.
When Eve tells her life story in the dressing room, she says "then the war came, and we got married. Eddie was in the air force - and they sent him to the South Pacific." The Air Force, wasn't formed until after the war in 1947. During the war it was called the Army Air Forces.
In the car, the snow tracks seen through the back window behind Karen curve to the left, whilst those behind Margo curve to the right.
Just before he enters Eve's suite, DeWitt swaps his cane from his left hand to the right. In following shot, shown from inside, he repeats the change.
At the beginning of Addison DeWitt's "introduction-speech" of everyone in the movie, he's supposed to look at the stage, but the rest of the audience behind him is clearly staring in a different direction.
In the dressing-room scene at the beginning, Margot turns in her chair to look at Karen. In the subsequent reverse angle, her arm positioning across the back of the chair has completely changed.
Sitting on the stair step behind Eve, Bill leans his right arm on his legs. In the subsequent shot, when she stands up, his right hand appears high about his head.
At right about 51:58 into the movie, when Margo and Lloyd are talking in the kitchen, right after Margo says "Cora...still a girl of twenty", the camera that is filming the scene shakes as if it was accidentally bumped.
When Addison and Eve are together in the Cub Room, he taps his cigarette holder to knock the ash off the cigarette, which falls out of the holder into the ashtray. He doesn't notice while he speaks, and keeps tapping the empty holder.