Continuity mistake: When Calvin Q. Calculus leaves his house when his wife says "You are going to regret it", the colour of the front door changes from dark brown to light brown between shots.
Continuity mistake: Shortly after the movie starts, Cal's plane lands and they go into the lab. Cal looks through a scope at an experiment and his assistant is next to him without glasses. After the experiment flames out, they show the men again but now his assistant is wearing glasses. (00:08:50)
Continuity mistake: When Tom's feline friends are sneaking past Spike in order to get to Tom's house, the ginger cat has a bandage wrapped around his tail, but when the three cats enter the house, the bandage on the ginger cat's tail has disappeared.
Continuity mistake: When the Coyote attempts to capture the Road Runner for the first time, he is standing on a bare patch of pavement surrounded by the puddle of glue he is spreading. In the next shot, the Coyote is now standing on glue with no bare patch, and when he realises he is about to be hit by the truck, he is standing on bare pavement in middle of the glue puddle once again.