In their work, public health managers face many unknowns. Contingency planning seeks to predict the events that will affect the organization’s ability to meet its mission; mitigates their potential negative implications; and, if possible, turns them into a public relations or political advantage. A well-known example of contingency planning in public health is planning for a natural disaster such as an epidemic of avian influenza or a manmade disaster such as a deliberate release of radioactive materials. These plans anticipate the demands of various scenarios, maximize effectiveness in response and minimize preventable morbidity and mortality. In addition, public health organizations must play a leading role in organizing the communitywide contingency planning for various types of disasters such as a severe earthquake, an outbreak of food poisoning that incapacitates large numbers, or a terrorist attack involving the release of poisonous chemicals. Communitywide contingency planning should also address interruption of utilities such as water, electricity, and natural gas. Failure to identify and plan for a variety of contingencies will prevent public health organizations and providers such as hospitals from meeting their obligations to the public and will raise significant questions as to the quality of their management. At least in the military, it is said that the plan of battle has no value after the first engagement. The same is likely to be true for the contingency planning undertaken by the organizations concerned with the public’s health. Besides obvious preparations such as periodic testing of communication links, emergency response and call-in drills, and knowing how to get emergency supplies of food and water, the public health organization’s response must be flexible and developed with full recognition of the need for communitywide coordination and cooperation.