The purpose of this study was to establish the frequencies of CYP1A1 and CYP2D6 polymorphic genotypes in the Tundra Nentsi population, which is a small indigenous northern people living in Siberia and belonging to the Northern Mongoloid race. The frequencies of Ile/Ile, Ile/Val, and Val/Val genotypes in the Tundra Nentsi population, as determined by means of the allele-specific PCR, were 50.8%, 39.2%, and 10%, respectively. Thus, the Val allele frequency in Tundra Nentsi appeared to be as high (29.5%) as in the Japanese population (25%) reported elsewhere. Those frequencies in the reference group of Siberian Caucasians were in good agreement with the data reported elsewhere for other Caucasians, although the Val allele frequency observed in Siberia inhabitants (5.7%) was somewhat higher than those frequencies obtained for other Caucasian populations. By means of PCR followed by specific-site digestion with MvaI endonuclease, we analysed the frequencies of CYP2D6B allele in the Tundra Nentsi population. The frequencies of 2D6wt/2D6wt and 2D6wt/B in the group of 120 Nentsi were 84.2% and 15.8%, respectively, with no subject possessing the 2D6B/2D6B genotype. The group of Siberian Caucasians represented those frequencies as 67.7%, 27.1%, and 5.2%, respectively. In total, the frequency of CYP2D6B allele in the Tundra Nentsi population was half that in Caucasians (8.3% vs. 19%). Taken together, our data indicate that the frequencies of CYP2D6B and Val allele of CYP1A1 in Tundra Nentsi population are different from those obtained for Caucasians. We also found similarities in the CYP1A1 mutation frequencies in the Tundra Nentsi and Japanese populations.