Both natural and man-made disasters, including the release of weapons of mass destruction, reveal a community’s preexisting vulnerabilities. The emergency response, and the nature of the disaster itself, combine to affect the short- and long-term health of the disaster-struck community. We will examine public health components of disasters, including emergency preparedness and response, relief efforts, health surveillance, and the ethical considerations of these activities. With case studies and readings, we will employ a public health perspective to understand the community impact of natural and man-made disasters in both developed and developing countries.