SNP 5mC/T (Chr1: 245618129) in DNA samples from the human blood of 92donors was studied by GlaI and FatI-PCR assay. The work includes a) isolation of DNA from the blood cells, b) GlaI and FatI-PCR assay of DNA fragment Chr1: 245617889 - 245618464, c) determination of 5mC (Chr1: 245618129) and thymine in DNA preparations and d) comparative analysis of the obtained results. It was shown that in position (Chr1: 245618129) 43 donors (46,74%) have a heterozygote (5mC/T), 28 donors (30,43%) have homozygote (T/T) and 21 donors (22,83%) have homozygote (5mC/5mC). Thus, taking into account a diploid set of chromosomes in the blood cells, SNP 5mC/T is observed in 99 positions from 184 (53,8%). The results obtained have shown that cytosine in position Chr1: 245618129 in the most of the blood DNA is methylated.