The mental health needs of youth in the juvenile justice system have received more attention at the federal level in the past 2 years than in the past three decades combined. The importance of the mental health issue is also being recognized at the state level. A number of factors have contributed to this change. They include: growing recognition of the mental health needs of youth in general; increasing reliance on the justice system to care for individuals with mental illness; and recent changes in the juvenile justice system. Despite this growing concern, there is a paucity of adequate research on the prevalence and types of mental health disorders in the juvenile justice system. However, these conclusions can be drawn: youth in the juvenile justice system experience substantially higher rates of mental health disorders than youth in the general population; a high percentage of youth in the juvenile justice system have a diagnosable mental health disorder; it is safe to estimate that at least one out of every five youth in the juvenile justice system has serious mental health problems; and many of the youth in the juvenile justice system with mental illness also have a co-occurring substance abuse disorder. A set of comprehensive strategies and models for dealing with mental illness in the juvenile justice system is emerging. It includes collaboration across systems, diverting youth with mental disorders from the juvenile justice system, mental health screening, community-based alternatives, and appropriate treatment. (Contains 47 references.) (MKA)