Effects of a musical manipulation on the challenging behavior of 3 persons with severe disabilities were evaluated. In Experiment 1 we identified stimulus conditions associated with high rates of challenging behavior for each participant. In Experiment 2 the high rate condition (determined in Experiment 1) was repeated with the addition of fast and slow beat music. Data indicate that challenging behavior was more frequent when slow beat music was played. Participants also displayed differential expressions of affect in these conditions. Results suggest that conditions associated with expression of affect may serve as establishing operations for challenging behavior and that this type of influence should be investigated further for possible contributions to intervention efforts.