Follow up, 138 men of reproductive age of the Moscow region were performed. The standard clinical examination with double spermogram analysis and determination of reactive oxygen species in the ejaculate was produced. Using the poly-merase chain reaction of DNA synthesis, we examined DNA samples of blood leukocytes for the presence of –262 C>T polymorphisms of the CAT gene. The semen analysis of 70 (50.7 %) patients showed pathospermia (main group). In 68 (49.3 %) men, we discovered normozoospermia (control group). In 35 (50.0 %) patients with pathospermia identified local mutations of the gene CAT. Also, 2/3 of the participants were registered with the heterozygous genotype (262СТ), and 7(10 %) men were marked by the genotype homozygous for the defective allele (262ТТ). In 1/3 of men with normozoospermia were found-ed local mutations of the CAT gene in both heterozygous and homozygous types. We defined a direct correlation between the level of reactive oxygen species and the frequency of CAT gene polymorphisms –262 C>T in infertile men (r=0.7). In conclusion, the CAT C–262T (rs1001179) gene polymorphism occurs in 50 % of cases in infertile men of Moscow region. Allele –262t of the СAT catalase gene can be considered as a genetic risk factor for oxidative stress and pathospermia. © Group of authors, 2019.