[en] Radiation accidents associated with the use of nuclear power, radiation devices and industrial applications have resulted in a number of individuals with significant partial or total body exposures, in a limited number with lethal outcome. Such exposures generally result in life-threatening suppression of bone marrow and immune functions and may be accompanied by high doses to the skin and underlying tissues. In recent years, new methods of diagnosis and treatment of such patients have entered development, while experience with relatively large-scale accidents, such as the Chernobyl cases, have clearly demonstrated the limitations of previous approaches. In particular bone marrow transplantation has met with limited success, mostly due to the inhomogeneous nature of accidental exposures as well as the frequent occurrence of other injuries other man bone marrow damage. Present day technology allows for direct estimates of the number of residual bone marrow stem cells to enable a rapid decision on the type of treatment indicated, while some twenty-five recombinant hemopoietic growth factors are under investigation to accelerate the recovery of white blood cells and platelets, as well as immune functions. If applied appropriately, such growth factor treatment will successfully replace bone marrow transplantation in the majority of accident cases. Advances in hemopoietic stem cell biology, both in terms of source of stem cells as well as their isolation, will on the other hand make stem cell infusion a much less risky operation than bone marrow transplantation has been in the past