The United Nations adopted an historic international Arms Trade Treaty (ATT) in April 2013. A 1997 meeting of Nobel Peace Prize laureates who called for an International Code of Conduct to address the 'destructive effects of the unregulated arms trade' initiated discussions that led to the Treaty. Public health institutions, including the World Health Organization and the International Committee of the Red Cross, and nongovernmental health groups such as International Physicians for the Prevention of Nuclear War, made adoption of the ATT a public health imperative. The poorly regulated $70 billion annual trade in conventional arms fuels conflict, with devastating effects on global health. The ATT aims to 'reduce human suffering'. It prohibits arms' sales if there is knowledge that the arms would be used in the commission of genocide, attacks against civilians, or war crimes. The health community has much to contribute to ensuring ratification and implementation of the ATT.