Summary. It was found that an increase in the adrenocortical and blood plasma11-HOCS concentration is seen immediately after emotional-pain stress (EPS) and72 to 96 hours following stress affection. An intesified thymic and splenic repopulationby cells, migrating from the bone marrow, occurs during the interval between 48 and192 hours following EPS. It was suggested that elevation of the corticosteroid levelin the organism in late periods after stress is directed to the cell population recovery.