Continuity mistake: When Rick goes to see Ferrari at the Blue Parrot the first time, there is a bottle on the table between them. Ferrari is shown taking the cap off the bottle, pouring a drink, and then returning the cap to the bottle. In the next cut, the bottle is gone, and in the cut after that the bottle is back, but without the cap, which should still be on it.
Continuity mistake: When Rick and Renault are sitting at a table outside Rick's Cafe, a bottle disappears from the table between one cut and the next and then reappears. In the shot without the bottle, there seems to be a champagne bottle at an angle in the background, something that is not visible in the other shots when the first bottle is on the table.
Continuity mistake: When Ilsa is in Laslo's bedroom, she is shown from behind looking out the window at the street below, then after an edit she is shown looking at the street from out side the window. The problem is that the first shot showed her looking through a roll-type window shade, and the second is a slat-type Venetian blind.
Continuity mistake: In scenes at Rick's Cafe, Captain Renault is wearing a white dress jacket with three medals. The right-hand medal, possibly the Légion d'Honneur, is first seen on a long ribbon. Less than a minute later, it is on a short ribbon; over the next nine minutes, it becomes long, short, long. It's not a medal, it's a yoyo.