Abstract Background Single nucleotide polymorphism (SNP) are the most common type of genetic polymorphism. SNP can significantly affect the expression activity of genes and the level of protein production. Researching the role of SNP in the occurrence of diseases is an important and urgent task, as it allows to predict the risk of pathology, its severity and outcome. Purpose of the study: study of the frequency of I148M polymorphism of the PNPLA3 gene in residents of the Republic of Sakha (Yakutia), associated with a high risk of steatosis and liver fibrosis. Methods A total of 3132 peripheral venous blood samples were used for population studies, studies patients with chronic hepatitis B and C, studies patients with NAFLD. Genotyping of DNA samples was carried out by real time-PCR. Reagent kits were used for genotyping I148M polymorphism of the PNPLA3 gene. Results In the present study, it was found that in the Yakut population the carriage of the GG genotype (49%) of the PNPLA3 gene I148M polymorphism predominates. When conducting a comparative frequency analysis, there were no statistically significant differences between the control group and the group with NAFLD patients(p=0,82). A comparative frequency analysis of the distribution of genotypes and alleles of I148M polymorphism of the PNPLA3 gene in the control group and the group of patients with chronic hepatitis B and C showed that we did not reveal significantly significant differences (p = 0.45). Conclusions The frequency of homozygotes for the mutant G allele of the I148M polymorphism of the PNPLA3 gene in the Yakut population significantly exceeds the frequency indicator of the G allele in other world populations.