This practice parameter presents recommendations for the mental health assessment and treatment of youths in juvenile detention and correctional facilities. Mental and substance-related disorders are significant public health problems affecting youths in juvenile justice settings. Sufficient time is necessary to conduct a comprehensive diagnostic assessment, interview collateral historians, and review pertinent records to identify primary and comorbid conditions. Potential role conflicts (i.e., forensic evaluator versus clinical care provider) need to be clarified before beginning any evaluation or treatment program, and particular attention must be paid to the issue of patient confidentiality. Issues of special concern in correctional health care, such as self-mutilative behaviors, suicide attempts, malingering, mandated reporting, ethical issues, cultural competency, institutional policies affecting clinical care, and the role of the clinician, are reviewed.