Revealing mistake: When Howard and Curtin chase Dobbs, they pass a dead donkey which is obviously breathing, and the rope used to tie its legs together is visible too.
Continuity mistake: Near the end, banditos murder Fred C. Dobbs and leave his stripped body by the waterhole as they go chasing after the burros, which they later try to sell in town. Within hours, Howard and Bob Curtin ride right past the same waterhole on their way to town, but Fred Dobbs' body is nowhere to be seen.
Visible crew/equipment: In the scene When Dobbs is panicking as he searches for the body of his not-so dead partner, who he had tried to kill the night before, he stumbles left and right. The camera pans a bit to far revealing the studio lot, building and fence, and a crew member sitting by a truck or machine.
Factual error: Based on the lottery poster, the movie is set in 1925. During the scenes in Tampico, numerous newer cars (closer to the 1948 filming) are present in the background.
Character mistake: When Curtin shoots Dobbs, the two shots are close together in time. When Curtin explains it he says that he was shot and falls. Then Dobbs shoots him again. This takes time but the shots were fired very quickly.
Continuity mistake: When Humphrey Bogart dunks his head in the watering hole, he leans over far enough that his hat is almost entirely submerged. In the next shot, he sets his hat down beside him and only the front portion is wet.
Other mistake: When the old man was resuscitating the unconscious boy he kept his arm sticking up in the air. His arm should have been besides his body, limp and unmoving.
