Spontaneous frequency of chromosome aberrations in 680 individuals of both sex (from newborns to centenariants) has been studied. The age dependence of the frequency of chromosome aberrations has been revealed. The distribution of individuals according to the frequency of their chromosome aberrations corresponds to the Poisson's law. The analysis of the age dynamics of the frequency of chromosome aberrations made it possible to define three age periods. The first period involves the newborns with a high level of chromosome aberrations; the second period--individuals at the age of 1 to 20 years with the lowest level of aberrations; and the third one--individuals over 30 years old with continuous increase in the spontaneous frequency of chromosome aberrations with the age.