Chromosome aberrations are the example of mutation process that happens at the chromosome level of DNA packing. The occurrence of inversions and complex translocations is not studied well enough due to the complexity of their detection methods. It is known that ionizing radiation is one of the factors that increases the frequency of CA. The objective of the pilot research was to study the frequency of inversions with involvement of telomere regions of the chromosomes and complex translocations in T-cells of 25 chronically exposed resi-dents of the Southern Urals. The studied individuals were subdivided into two groups. In the first group consisting of 12 exposed people (11 women and 1 man) inversions were studied with Q-FISH in. Doses ranged from 0.001Gy to 2.9 Gy. In the second group comprising 13 people (9 women, 4 men) complex translocations were analyzed with M-FISH in. Doses ranged from 0.5–3.1 Gy. The groups did not overlap. As a result of the analysis it was revealed that complex translocations occur 6 times less frequently than simple ones ( р < 0.001). Chromatid variants of inversions predominated as compared to chromosome ones (9:0.17 per 100 cells, p < 0.001). No dependence of the studied parameters on exposure dose to red bone marrow was noted.