The effect of a Snoezelen room on the disruptive and prosocial behavior of three male, autistic inpatients was examined. In an ABAB reversal design, specific disruptive and prosocial behaviors were recorded for each client throughout the four 28-day periods of the study. Results indicated that the three clients had different responses to the room, but no client showed a decrease in disruptive behaviors while in the Snoezelen condition compared to baseline, and one client showed a clear pattern of increased disruptive behavior during the Snoezelen periods. There was a slight tendency for clients to engage in more prosocial behaviors while in Snoezelen. These findings do not support the contention that Snoezelen rooms are effective interventions for aggressive behavior in this client population.