This study compares the neuropsychiatric, intellectual, and educational status of extremely violent and less violent incarcerated boys. The more violent children were more likely to demonstrate psychotic symptomatology (paranoid ideation and rambling, illogical associations) and to have major and minor neurological abnormalities. They were also more likely to have experienced and witnessed extreme physical abuse. The contribution of these factors to violent delinquency is discussed, and implications for therapeutic intervention are suggested.