Goofs

The black cat that attacked Florence and that she later found dead in the shower, is later seen on the outside wall.

When the ghost runs out of Florence Tanner's room, you can clearly see a 2x4 board that was part of the mechanism to make the door open and close by itself.

Pull wire is visible when Fischer is thrown back during the exorcism scene toward the end of the film.

Visible wire pulling back the covers of Florence's bed.

In the film's opening credits, there is a spelling mistake. The copyright line reads "... 20th Century Fox Film Corpoation".