Behavior therapists on child and adolescent psychiatric inpatient units have played an increasing role in the treatment of a wide range of disorders. Indeed, behavioral assessment and treatment strategies in these settings have been applied to a diversity of problems, including depression, mental retardation, autism, conduct disorders, attention deficit hyperactivity disorder, anorexia, and bulimia. More recently, the heuristic value of behavioral methods with substance abuse, pediatric pain, and child maltreatment has been documented as well. Because of the multifaceted and complex challenges posed by children and adoles cents who reach inpatient units, behavioral clinicians have worked close ly with other professionals (e. g. , psychiatrists, social workers, psychi atric nurses) in an effort to provide broad-spectrum, comprehensive intervention. However, as a burgeoning body of clinical research attests, the significant contribution of behavior therapy to successful treatment outcome is now indisputable. Yet, surprisingly few texts have been published concerning inpa tient treatment of children and adolescents. The few extant efforts in this area have not covered the broad array of issues and diagnostic popula tions treated, nor have they considered the pragmatic day-to-day diffi culties encountered by behaviorally oriented practitioners working in child and adolescent inpatient settings. This text is an attempt to remedy such shortcomings by providing a comprehensive yet practical approach to the functions of behavior therapists on inpatient psychiatric services for children and youth.