Quality of sperm and some parameters of LPO reflecting primary and end stages of oxidation and levels of a-tocopherol and total antioxidant activity were studied in ejaculate samples from 130 men (mean age of 24 years) living in Ulan-Ude, Buryatia Republic. All participants took a part in survey and were examined by an andrologist. The observed peculiarities of LPO and antioxidant defense in Russian men, such as decreased level of substrate supply for the processes of LPO and a-tocopherol, attest to specificity of metabolic processes and development of compensatory reactions of the organism under physiological conditions. LPO processes were more active in Buryat men, which can indicate exposure of cell membranes to toxic oxygen species. However, the observed in these patients significant increase in a-tocopherol concentration reflects adequate functioning of the adaptive and protective mechanisms of the body.