The National Institute of Mental Health (NIMH) and the National Institute on Drug Abuse (NIDA) have a long history of supporting investigator-initiated research and research training to enhance the scientific understanding of and effective interventions for a range of problems associated with youth violence. New technologies are emerging and basic research has promise for increasing our understanding of how biological factors operate in conjunction with other factors to contribute to violent behavior, psychopathology, and drug abuse. This article describes emerging areas and directions for research in this important area of public health.