This clinical case study investigated the effectiveness of a multicomponent intervention for a child with autism and anxiety-related problem behavior that integrated components of cognitive behavior therapy (CBT) with positive behavior support (PBS). One child with autism and his family participated. The dependent variable was the number of steps that the child completed in an anxiety hierarchy during exposure sessions in one or more shopping malls. A changing criterion design evaluated improvements in child behavior. The design had three phases: implementation with interventionists, maintenance and generalization with family, and follow-up. Direct observation results during implementation with interventionists documented stepwise improvement in child behavior consistent with the steps in the anxiety hierarchy. Parent verbal report during the maintenance and generalization phase indicated that the child's ability to ride on escalators maintained and generalized. Follow-up data collected 24 months post intervention indicated continued success. Results are discussed in terms of limitations, implications, and future research.