Continuity mistake: When the Dude is in Jackie Treehorn's estate, he pencils over a pad of paper to see what Jackie wrote down while he was on the phone. He then hurriedly crumples up the piece of paper and shoves it in his wallet. Then, when we see the Chief of Police of Malibu looking through the contents of The Dude's wallet, the paper is there, neatly folded in fourths.
Continuity mistake: The Dude's driver's-side door is unusable after his car is stolen and retrieved, and we see him using the passenger door at least once after he takes the car home. But then at Larry Sellers' house, which they visit pretty soon, The Dude gets out of the driver's door as if nothing had happened; I doubt he'd have bothered to have it fixed in that short time. (01:09:00)
Continuity mistake: There's one scene where The Dude is taking a bath, and three Germans threaten him with a marmot (actually a ferret). When they take the little animal out of the water, you see Dude's head and in the back four candles: yellow, blue, red and white. The yellow and red one aren't burning; the blue and white are. The next shot of the Dude's head you see that the yellow, blue and red candles are burning, the white one isn't.
Continuity mistake: When The Dude enters Lebowski's office the telephone is on the far right of the desk and the lamp is on the far left with 3 wooden objects between them. During the shots of The Dude, when he is talking, the phone and lamp are much closer together and the wooden objects aren't there. (00:12:00)jle
Continuity mistake: When the Dude shows up at Maude's place (the time where the video artist is laughing annoyingly), pay attention to Maude's bangs changing positions between several shots. Sometimes the hair is raised up on the left side of her forehead and other times the bangs are straight across. It's most noticeable after she pours a drink and turns around.
Continuity mistake: When the Dude joins Mr. Lebowski in the West Wing, where he was in seclusion, he is handed Bunny's ransom note by Brandt. As he reads the note he smokes a joint. Through the entire reading sequence he moves the joint from his mouth to his hand and back. Watch how several times the joint is in his hand, while you see a shot of the note and the Dude's hands, but when the shot changes to overall view, the joint is suddenly back in his mouth and he retrieves it again.
Continuity mistake: When the Dude's driving home from the doctor's, he passes a yellow truck, visible through the side window, when he throws his joint against the door window. If you compare the shot where he grabs for his joint and the next one where he sprinkles the beer, you'll see he passes the truck twice. (01:05:35)
Continuity mistake: When Lebowski is driving home from the doctors office, the back window of his car is so covered with dirt that you cannot see out of it, yet when he looks in his rearview mirror there is a very clear reflection of the car following him. (01:05:00 - 01:16:00)