In the past decade, interest in the operational and epidemiologic aspects of disaster medicine has grown dramatically. State, local, and federal organizations have created vast emergency response networks capable of responding to disasters, while hospitals have developed extensive disaster plans to address mass casualty situations. Increasingly, the US armed forces have used both their ability to mobilize quickly and their medical expertise to provide humanitarian assistance rapidly during natural and man-made disasters. However, the critical component of any disaster response is the early conduct of a proper assessment to identify urgent needs and to determine relief priorities for an affected population. Unfortunately, because this component of disaster management has not kept pace with other developments in emergency response and technology, relief efforts often are inappropriate, delayed, or ineffective, thus contributing to increased morbidity and mortality. Therefore, improvements in disaster assessment remain the most pressing need in the field of disaster medicine.