The World Health Assembly (WHA) adopted the new International Health Regulations (IHR) on May 23, 2005.1 The new IHR represent the culmination of a decade-long revision process and an historic development for international law and public health. The new IHR appear at a moment when public health, security, and democracy have become intertwined, addressed at the highest levels of government. The United Nations (UN) Secretary-General Kofi Annan, for example, identified IHR revision as a priority for moving humanity toward "larger freedom."2 This article analyzes the new IHR and their implications for global health and security in the 21st century.