Danny DeVito was Steven Spielberg's first choice for the part of Barney. DeVito felt his acting style was too gruff to properly portray Barney, and turned the part down. Subsequently, DeVito recommended Rick Moranis for the part.
Since the entire cast performed barefoot, glassware was banned from the set to prevent injuries.
The appearance of the Flintstones' sabre-toothed cat marks one of the first times for a furry CG character in a feature film. A specific, complex algorithm (for its time) had to be developed to calculate the movement of every single hair of the fur.
The "Bowling Alley" sequence was almost not in the film. It was added at the last moment, because Fred's "Twinkle Toes" bowling style was such a big part of the series, they felt they couldn't leave it out.