Continuity mistake: As Mrs. Wadsworth reads the letter from Ann, the positions of Alba and Germaine instantly change from close to each other to apart as the scene cuts.
Continuity mistake: As the Wadsworth ladies drive up to Ann's house, Alba is looking out the left rear window. The next shot and she is on the right side of the car.
Revealing mistake: The square base holding the knife in Alba's back is visible.
Continuity mistake: Ann is several feet away from the baby with her husband, but a quick close up of the baby shows her right next to the baby.
Continuity mistake: Ann and Germaine change positions between shots while conversing in front of Ann's car.
Revealing mistake: When Mrs. Wadsworth is whipping the babysitter, the babysitter's stunt double is obvious due to the style and color of her hair.
Continuity mistake: The newspaper in Alba's hand changes position while she speaks with Ann and the baby.
Continuity mistake: The file on the Wadsworth baby is visible in the front views of Ann and the doctor, but disappear in the views over the doctor's left shoulder.
Continuity mistake: At the baby's birthday party, Mrs. Wadsworth's hands are free as she speaks to the guests, but in the next shot her hands are on the sofa arm, clasped in the baby's hands.
Other mistake: After the baby opens the door to the basement and enters it, the door closes by itself, but there is no closing arm to close the door.
Continuity mistake: The restraining ropes around Ann's wrist immediately change length from her wrists being tied close together to four inches apart before using the saw to slice through them.
Revealing mistake: The babysitter's stunt double has a different hairstyle and color than the actress playing her as Mrs. Wadsworth whips her.
Continuity mistake: The newspaper in Alba's hand changes position while speaking with Ann and the baby.
Continuity mistake: The file folder on the Wadsworth baby is visible in the front views of Ann and the doctor, but disappears in the views over the doctor's left shoulder.
Continuity mistake: At the baby's birthday party, Mrs. Wadsworth's hands are free as she speaks to the party guests, the next shot her hands are on the sofa arm, clasped in the baby's hands.
Other mistake: The basement door of the Wadsworth's house closes itself after the Baby enters. Previous scenes show the door cannot close and shut itself.
Continuity mistake: The rope ties around Ann's wrist immediately change length from close together to several inches apart before she uses the saw to slice through the ropes.
Continuity mistake: The positions and distance of Alba and Germaine change instantly from close to far apart as the scene cuts while reading Ann's letter.
Continuity mistake: When the Wadsworth ladies drive up to Ann's house, Alba is looking out the left rear window of the car. The next quick shot shows Alba on the right side of the car.
Visible crew/equipment: Movie set lights are reflected in the windows of the door as Alba enters Ann's house.