Phenotypes of alpha 1-antitrypsin of 218 natives from three ethno-historical regions of the Kazakh SSR were detected by isoelectric focusing in ultrathin layer polyacrylamide gel. Gene frequencies of the PiM1, PiM2, PiM3 subtypes in the summary extract were as follows: 0.8477, 0.1372 and 0.0106, respectively; the total gene frequency of two rare variants (PiN and PiZ) was 0.0046. The observed distribution of Pi subtypes shows good agreement with the Hardi-Weinberg equation. The analysis of the interpopulation intraethnic variability of the alpha 1-antitrypsin phenotype and allele frequencies in Kazakhs revealed clear local diversity. The frequency of PiM1 in the natives from North-Central ethno-historical region was reliably lower and that of PiM2 higher than in populations from South-East and West regions. The extracts analysed did not differ in the PiM3 incidences. The results of these studies were compared with the literature data for alpha 1-antitrypsin polymorphism in populations of the Euro-Asia. It is shown that PiM1 and PiM2 frequencies in the Kazakhs differ from the corresponding mean values both in mongoloid and europeoid groups. At the same time, they do not correspond to the intermediate frequency estimations, which could be expected from the fact of mixed origin of the Kazakh people and their border-line geographical position between Europe and Asia. Possible reason for such discrepancy is discussed.