Increasingly health personnel are called on to address the needs of adolescents affected by armed conflict. Adolescents suffer as combatants, direct and indirect casualties, as dependents of combatants, and as citizens of countries whose resources are destroyed and/or consumed by war and other forms of organized violence. Survivors of war, ex-child soldiers, refugees, and others are found today in cities on all continents. This paper will review the epidemiology of armed conflict, especially with respect to children and youth, examine the etiology of youth involvement in armed conflict including social risk factors and developmental vulnerabilities, and review the peace-building efforts of the United Nations, communities, and youth themselves. Finally we will briefly review the efforts of those committed to the well-being of adolescents in the areas of advocacy and treatment.