On the basis of the results of long-term observations, general laws have been identified determining the dynamics of 90Sr concentration in the bone tissue of the population of the USSR in 1959-71, the peculiarities of 90Sr accumulation in different age groups and the connection and dependences between the intake and the contect of the isotope in human organism. It has been found that maximum 90Sr concentration occur in children born in the year when nuclear tests were carried out. The type of distribution of the frequency of occurrence of cases showing different levels of 90Sr content in uniform population groups was determined. Characteristic features of 90Sr distribution in different bones of the skeleton and its changes in the course of time were demonstrated.