We studied the bone marrow of various localization taken during autopsy of the humans died as a result of accident at the Chernobyl Nuclear Power Station and experimental animals (frogs and rats) subject to external gamma (gamma-irradiation at lethal doses (SD 100). It was shown using histological, histochemical and electronmicroscopic methods that the early radiation death of the bone marrow hemopoietic cells, so-called "early necrobiosis", is realized by apoptosis. During the period of recovery, apoptotic death of the hemopoietic cells also takes place, which, being expressed simultaneously with the onset of hemopoiesis, directly correlates with the intensity of repair. It was proposed that apoptosis as a physiological contrast of mitosis, arises during the early postradiation period as a response to blockade of mitotic activity and causes its abortive rise and bone marrow cellularity. During the recovery period, apoptosis may not only passively accompany mitosis but stimulate proliferative processes.