The report summarizes the work of a committee convened to define, in light of present knowledge, the best plan for medical management of large numbers of radiation casualties under austere medical conditions and to evaluate specific courses of research which would improve our ability to cope with civil defense aspects of radiation sickness. Radiation injury is viewed as only one of a number of noxious agents which might be expected to act cumulatively or synergistically under the shelter conditions postulated. The medical significance of pre-existing disease and disability in the shelter population and the medical effects of confining large randomly selected groups of persons under the austere conditions postulated are emphasized throughout. Measures most likely to influence ultimate radiation-related mortality include management of infection and of hemorrhagic manifestations of radiation injury, and management of surgical problems. Presently available chemical 'protective agents' are mentioned but their effectiveness in preventing radiation mortality is considered to be doubtful under shelter conditions postulated. Space and water are the most important requirements for survival under shelter conditions, and present allocations should be revised. Recommendations for specific research are made but these recommendations would be subject to revision, depending upon the outcome of the recommendations with respect to operations. (Author).