Genotyping for polymorphisms in 6 genes (platelet glycoprotein Ilia, Factor I, Factor II, Factor V Leiden, PAI-1, methylenetetrahydrofolate reductase (MTHFR)) was conducted in 15 children with disturbances of brain blood circulation. Frequencies of homozygous variant GG for the -455G/A polymorphism of the fibrinogen (Factor I) gene and mutation 1565T/C of the glycoprotein Ilia gene were higher (p<0,05) in patients comparing to the controls, 26,6% and 2,8%; 26,6% and 20,2%, respectively. Frequency of the homozygous variant TT of the MTHFR C677T polymorphism was higher (p<0,05) in patients with stroke than in the controls (26,6% and 20,2%, respectively). Homocysteine level in children with stroke, in particular in carriers of the TT C677T MTHFR genotype, was higher (11,2 +/- 1,5 rmol/ L) comparing to other genotypes (a normal value 8,1 rmol/L). Mutations of Factor II 20210A and Factor V Leiden were not found. Therefore, combinations of 2 and 3 risk genetic variants were observed in 60% of patients.