The occurrence of industrial and medical radiation accidents and the threat of terrorist events involving radioactive material mandate the development and implementation of an appropriate medical response. Medical professionals who would logically be involved in such events include, among others, radiation safety officers, radiologists, radiation oncologists, nuclear medicine physicians, emergency department physicians, hematologists, medical oncologists, gastroenterologists, infectious disease specialists, as well as primary care providers. All will be asked to play a significant role in evaluating and treating victims of an accidental or deliberate exposure to radiation. Due to their experience in managing patients with cytopenias and/or marrow aplasia, hematologists will most likely be asked to take primary or consultative responsibility for medically treating individuals exposed to a moderate or high dose of radiation.