Psychopharmacological prescriptions for preschoolers with disruptive behavior disorders and ADHD are on the increase, often because of a lack of access to proven interventions for this age group. This Workshop familiarizes participants with an evidence-based treatment modality for disruptive preschoolers that has demonstrated statistically and clinically significant improvements in behavior: Parent Child Interaction Therapy (PCIT). The theoretical and empirical basis of this treatment is described; assessment procedures that guide the course of treatment and evaluation of treatment are documented; the basic PCIT skills that parents learn are outlined; the change in child disruptive behavior during treatment is illustrated; and therapist skills required for delivery of PCIT are reviewed. Participants gain a thorough understanding of PCIT and its usefulness in the treatment of preschoolers.