Results indicated that even when conduct disorders were excluded from the analysis, 60 percent of male and 70 percent of female juvenile detainees met diagnostic criteria for one or more psychiatric disorders. Moreover, the rates of comorbidity (the presence of more than one psychiatric disorder) in the detainee population were significantly higher than those reported in community samples. Particularly high rates of depressive disorders, in particular depression and dysthymia (minor depression), and substance use disorders were discovered in the detainee population, which places these detainees in higher risk categories for suicide and disruptive disorders. Other findings indicate that over half of the youth in the juvenile justice system are African-American or Hispanic, leading to greater numbers of minorities who meet criteria for psychiatric disorders. Participants were a stratified random sample of 1,172 male and 657 female youth who were arrested and detained at the Cook County Juvenile Temporary Detention Center in Illinois between November 1995 and June 1998. Participants were administered the Diagnostic Interview Schedule for Children (DISC) Version 2.3, a widely accepted and reliable measurement tool for the assessment of psychiatric disorders in young people. Data analysis involved weighted prevalence estimates to reflect the detention population. Findings are presented by demographic subgroups (gender, race/ethnicity, and age) for six categories of disorder: affective disorders, psychosis, anxiety, attention-deficit/hyperactivity disorder (ADHD), disruptive behavior, and substance use. Future research should focus on the most common pathways to comorbidity, critical points in the development of psychiatric disorders, and how these factors differ by gender, face, and age. Tables, figures, references