The bar owners are suing in federal court, saying the smoking ban is unconstitutional. They say they're being treated unfairly because they are covered by the ban but casinos are not.
Attorneys for the state also filed motions Friday. They argue that casinos aren't like bars and can be treated differently.
The ban went into effect July 1. It prohibits smoking in bars and most other public places but exempts casinos, cigar bars that opened before 2006 and the Denver International Airport smoking lounge.
Private workplaces with three or fewer employees are also exempt.