A multivariate, criterion-referenced approach was used to assess prevalence of serious emotional disturbance among children on protective service case loads. Of 140 recipients of protective services, 72% were statistically indistinguishable from children in Washington State's most intensive mental health treatment programs. School problems, substance abuse, and antisocial behaviors were common in the sample, as were family histories of mental illness or substance abuse. Greatest service needs included family support groups, outpatient treatment, school-based treatment, and diagnostic services. These results underline the importance of structural changes to facilitate cross-system collaboration between mental health and protective services.