Climatic and geographical features always influenced on adaptation to the environment as well as the development level of economy and culture. The formation of certain food behavior in population determined fixation of specific gene alleles and mutation. They were responsible for digestion a typical food for the population. At the moment there is information about such genetic features as metabolism of proteins, carbohydrates and fats for many races and nations. But a few studies are about causes of prevalence differences of gene polymorphisms of folate cycle in the world's populations. The main objective was to explore 677C>T mutation MTHFR gene among Russian and Buryat to compare it with ones in other populations. The total of399 children and adolescents (200 Russians and 199 Buryats) were involved in this study. Genotyping of MTHFR 677C>T was performed by PCR-RT We used soft "STATISTICA 8.0" to compare results. As a result, T-allele frequency was 30 % in Russians and 21,1 % in Buryats. We found significant differences of prevalence of polymorphism 677C>T between studied groups (p = 0.011). Also we found significant difference between Russian and British (p = 0.054), French (p = 0.0263), Spanish (p < 0.0001), Italian (p < 0.0001) and Greek samples (p = 0.0454). The Buryat group had significant differences with Chinese (p < 0.0001), Korean (p < 0.0001), Mongolian (p < 0.004), Japanese (p < 0.0001), Kazakh (p = 0.0198) samples and two samples of Hans (p < 0.0001; p = 0.0390).