This article describes 5 communication challenges faced by the author as she managed the communication response by the Centers for Disease Control and Prevention to the anthrax attacks of 2001: communicating uncertainty, selecting credible spokespersons, collaborating with other organizations, satisfying a competitive 24/7 media, and speed. The lessons learned in responding to these challenges led to profound changes in the way communication was organized in the agency. These changes are described within the framework of chaos theory.