Untoward events involving radioactive material, either accidental or intentional, are potentially devastating. Hematologists and oncologists are uniquely suited to help manage radiation victims, as myelosuppression is a frequent complication of radiation exposure. In the aftermath of a large event, such as a nuclear detonation, there may be a national call for surge capacity that involves hematologists/oncologists across the country in the disaster response. In preparation, the National Marrow Donor Program and American Society for Blood and Marrow Transplantation have established the Radiation Injury Treatment Network (RITN), a voluntary consortium of transplant centers, donor centers, and umbilical cord blood banks. RITN is partnered with the Office of the Assistant Secretary for Preparedness and Response in the United States Department of Health and Human Services to develop treatment guidelines, educate healthcare professionals, coordinate situation response, and provide comprehensive evaluation and care for radiation injury victims. We outline the current plans for event response and describe scenarios, including catastrophic events that would require extensive support from hematologists/oncologists across the country. In addition, we highlight important reference resources and discuss current efforts to develop medical countermeasures against radiation toxicity. Practitioners and institutions across the country are encouraged to become involved and participate in the planning.