Self-injurious behavior represents a significant barrier to behavioral interventions with retarded children. The etiology of this behavior is hypothesized as secondary to a state of overarousal. β blockers are believed to be uniquely useful medications in having an effect on self-injurious behaviors through their ability to reduce arousal in the face of stimulation and demands. The case presented describes a multiply handicapped adolescent with severe self-injury who responded to 300 mg of propranolol with a gradual but steady reduction in self-injury over 12 months. Concurrent with this was the emergence of increased interactions and benefit from behavioral interventions.