Mass-care events, such as pandemic influenza, could reach such devastating proportions that there will be the need to make difficult triage decisions that will ultimately result in the deaths or severe disability of patients in large numbers. The method by which we determine how triage of scarce health care resources will be performed must be clearly defined prior to a disaster event. This paper will discuss several of the ethical principles that must be weighed in developing a mass-care triage plan, as well as steps to facilitate its implementation. Development of triage policies in such an event should be developed in an open and transparent manner, be reasonable in design, include the views of the critical stakeholders, and be responsive to and provide a mechanism for accountability, with a clearly defined goal of the just triage of limited health care resources. Planning failure will result in increased deaths from poor triage processes and substantial mistrust of the health care system and its practitioners.