"Triage" is a term generally referring to the social practice of sorting or categorizing. While it originally had an innocent, commercial meaning referring to sorting crops according to quality, the term quickly took on a more ominous meaning referring to classifying battlefield casualties into three groups: those too well-off to be treated and then, among those more seriously wounded, one group that will get medical attention and another that will not. The moral problem is how to distinguish between the latter two groups. The Hippocratic oath has been utterly useless in helping us do this sorting, since the oath commands the clinician to remain loyal to the individual patient and give no attention to the choice between two patients with different needs. Baker and Strosberg show that historically the British sorted following utilitarian principles, giving priority to the patients who could benefit the most even if they were not in greatest need, while the French arranged patients who could be helped in order of greatest need even if it was not maximally efficient to do so. Understanding how contemporary organ transplant policy utilizes triage can help us clarify our mass disaster triage policy. Two organ transplant examples--tissue typing for kidneys and geographical priority for allocating livers--show that American social policy, when forced to choose between allocating on the basis of efficiency or allocating on the basis of justice, will consider both principles, but give equal or dominant priority to justice--even though this priority is understood to be relatively inefficient. Since health care professionals have a recognized preference for efficiency over justice and lay people are inclined towards justice, leaving mass disaster triage policy in the hands of health professionals will predictably structure the policy in a way that conflicts with the moral priorities of the lay population. Formal public debate that recognizes the conflict between efficiency and equity--professional and lay priorities--is therefore essential.