A behavior therapy approach for obtaining cooperation during needle sticks was provided to 8 pediatric patients with intellectual and developmental disabilities. Therapy was provided during mock needle sticks. Hand lotion was applied to simulate topical anesthetic. Distracting activities established relaxation while needle stick materials were gradually introduced. Positive reinforcement was provided for cooperation. Behavioral distress was ignored, blocked, or redirected. After cooperating with mock needle sticks, needle sites were prepared with topical anesthetic (EMLA), then therapists and medical staff implemented the behavioral protocol while completing the actual needle stick(s). Observational measures of cooperation and interfering were obtained. Results were replicated across 8 children and evaluated using paired samples t tests. Initially, all children were uncooperative with needle sticks. With treatment, behavioral distress decreased, and patients cooperated with mock and actual needle sticks. Results support the effectiveness of behavior therapy for promoting cooperation in children with intellectual and developmental disabilities during needle sticks.