In 1996, NATO issued guidance for the exposure of military personnel to radiation doses different from occupational dose levels, but not high enough to cause acute health effects-and in doing so set policy in a new arena. Scientific and technological developments now permit small groups or individuals to use, or threaten to use, destructive devices (nuclear, biological, chemical, and cyber-based weaponry, among others) targeted anywhere in the world. Political developments, such as the loss of political balance once afforded by competing superpowers, have increased the focus on regional and subregional disputes. What doctrine should guide decisionmaking regarding the potential exposure of troops to radiation in this changed theater of military operations? In 1995, the Office of the U.S. Army Surgeon General asked the Medical Follow-up Agency of the Institute of Medicine to provide advice. This report is the final product of the Committee on Battlefield Radiation Exposure Criteria convened for that purpose. In its 1997 interim report, Evaluation of Radiation Exposure Guidance for Military Operations, the committee addressed the technical aspects of the NATO directive. In this final report, the committee reiterates that discussion and places it in an ethical context.