Data on the frequency of inbreeding in some isolated populations of Samarkand region are given. Statistically significant differences were established in the frequency of inbreeding in separate groups and in the general population of the region. Inbreeding marriages were more observed between paralel cousins, occasionally they were made between secon cousins. Strict time dependence of inbreeding frequency was not found, but it was noticed that the level of inbreeding was reduced since 1930 to 1949.