Folate cycle is the supplier of one-carbon fragments for such vital cellular processes as regeneration of methionine, biosynthesis purines, metilation DNA and RNA. Polymorphic mutations can lead to individual differences in a level of expression of genes of participants folate cycle that causes various infringements of a metabolism folate. In the given work we have defined frequencies of occurrence alleles and geno-types of polymorphic loci C677T of a gene 5-, 10-methylenetetrahydrofolate reductase (MTHFR), G1938A of a gene methylenetetrahydrofolate dehydrogenase 1 (MTHFD1), A2756G of a gene methionine synthase (MTR) and T833C / 844ins68 of a gene cystathionine β-synthase (CBS) in casual sample of inhabitants of Novosibirsk.