The authors carried out cytogenetic studies on lymphocytes from human peripheral blood of 105 persons--49 women and 56 men in order to examine spontaneous frequency of the structural chromosomal abberations in the somatic cells. There were 191 cells with abberations (1,17%), out of 16,267 analyzed metaphasic plates. They found 0,39% of chromatid fragments, 0,71% of chromosomal fragments, 0,06% dicentricets, 0,01% of symetric and asymetric chromatid exchanges and 0,006% of rings. There were no statistically significant differences in the discovery of the spontaneous abberations in the examined persons at various age and sex.