Continuity mistake: During the show's first two seasons, we are told Roseanne had a more slender figure during her younger years and didn't start gaining weight until after she began having kids. Later in the Halloween episode, "The Ghost of Halloween Past," Roseanne is shown her past, and her younger versions are not slender.
Continuity mistake: In the episode where Jackie takes over the house, while Roseanne is at their parents. DJ comes in the kitchen and is sent in the laundry area for a shirt. Before he goes in there he is wearing a pair of dark jean with nothing on them. He comes back a second later with his head stuck in a shirt still with the same pants on. But when he finally pops his head through the shirt his pants have changed to a pair of stonewash, with what looks like bleach stains on the front. A wide shot of the kitchen in the next frame and his pants are back to the dark ones with nothing on them.