Despite the tremendous mental health need evidenced by children in foter care and their high rates of use of mental health services, little is known about the impact of outpatient mental health services, little is known about the impact of outpatient mental health services on the behavioral health of this population. This chapter describes a study which utilized data from the National Survey of Child and Adolescent Well-being (NSCAW), the first nationally representative study of child welfare in the United States. A sub-sample of 439 children who have experienced long-term foster care were included in this study. These data were used to estimate the impact of outpatient mental health services on the externalizing and internalizing behavior problems of children in long-term foster care. A propensity score matching model was employed to produce a robust estimate of the treatment effect. Results indicate that children who have experienced long-term foster care do not benefit from the receipt of outpatient mental health services. Study results are discussed in the context of earlier research on the quality of mental health services for children in foster care.