Comorbid psychiatric conditions often complicate the treatment of childhood obsessive-compulsive disorder (OCD). Behavioral treatment of OCD using exposure plus response prevention for a boy with disruptive behavior disorders and two previous unsuccessful medication trials is described. Treatment was adapted to his developmental level, his mother was highly involved in treatment, and a contingency management program contained his disruptive behavior so that he could participate in therapy. Posttreatment and 2− and 6-month follow-up measures indicated marked improvement in OCD symptoms. The possibility of successful behavioral treatment of OCD in medication-free children with disruptive behavior problems is highlighted. J. Am. Acad. Child Adolesc. Psychiatry, 1998, 37(4):443–446.