First responders (police, fire department, and EMS) remain the primary focus for most ongoing disaster preparedness efforts. However, as mandated by the Joint Commission on Accreditation of Healthcare Organizations (JCAHO), all hospitals must have a functional disaster plan. As we learned during the recent SARS dilemma, the intensive care unit (ICU) is a key element of a hospital's response to large-scale incidents. In addition to emerging infectious diseases, trauma, bioterrorism, chemical attack, and radiation-induced injury are possible occurrences. Unfortunately, there is little written in the medical literature about the effects on structure and function of an ICU during a disaster.1,2 As one example, during a biological weapons attack or an outbreak of a highly contagious disease, the ICU physician will be called on to recognize the syndrome and initiate the appropriate investigation and therapy. Therefore, the ICU medical director must be intimately involved with the hospital disaster committee to ensure the optimal use of this limited resource, and to ensure that the proper training and equipment are accomplished and available. The purpose of this chapter is to educate the intensivist on the general components of a hospital disaster plan, to detail where an intensive care unit fits into the hospital preparedness plan, and to review what predisaster preparation initiatives an ICU should conduct.