Despite the ever-present risk of mass-casualty incidents (MCIs) in all geographical regions, there is a limited body of literature detailing specifically how an intensive care unit (ICU) prepares for such an event. When responding to an overwhelming volume of severely injured victims, the intensivist must make a paradigm shift away from providing complete care to all patients to one of preferentially administering care to those with the greatest likelihood of survival. To do this effectively, ICU directors must possess a detailed understanding of the entire disaster response, including organization, triage, staffing, and treatment. This article provides a comprehensive review of each of these topics, as well as a framework on specific elements of critical care and treatment based on published literature and expert opinion to assist the clinician in directing care to where it is most appropriate.