The applicability of a riser simulator reactor for ascertaining the yields of gases, gasoline, LCO (Light Cycle Oil) and coke in commercial catalytic cracking units has been studied by using both a feed and an equilibrated catalyst from a refinery. The bench scale unit operates under the industrial conditions (temperature, catalyst/feed ratio, time on stream), for which conversion and yields of gasoline, gases, LCO and coke have been determined.