Correct decision making may have far-reaching consequences. Triage is an area in which decision-makers must know what they are doing, why they are doing it, and which actions to take to achieve a satisfactory outcome. Triage has its origins in military history and today is used in a variety of medical settings. In this article we focus on the role of triage in disaster situations, its application in military settings, and its use in disaster medicine. Useful concepts enabling correct decision making by the triage officer include the application of computer technology and a review of methods of patient categorization. The dynamic nature of triage and the role of the triage officer as part of a team approach to disaster patient management are highlighted. We explore techniques for the successful training and education of triage officers and investigate a model of the emergency physician as the triage officer.