Glutathione plays a key role in protecting cells from oxidative stress. Disruption of antioxidant is characterized by the development of free radical damage of various components of cells and tissues that makes up the lipid’s peroxidation, which is a factor of the pathogenesis of various pathologies. It is known that organism  31 contains 2 forms of glutathione: oxidized disulfi de (GSSG) and reduced (GSH) forms. Oxidants react with GSH, giving disulfi de GSSG, which can be converted back to GSH with the help of reductase enzymes. 17 swimmers of 15-18 y.o. were selected for studies. The concentration of oxidized glutathione in erythrocytes was determined by method of ion-exchange liquid chromatography at amino acid analyzer AAA T339M. The concentration of oxidized glutathione is increased both at intensive physical activity (76.7%) and emotional stress in erythrocytes during the competition (87.8%) at a wide range, refl ecting the different degree of adaptation of individual athletes to emotional stress. The revealed nonspecifi c changes - increase of oxidized glutathione in erythrocytes under stress, may serve not only as a marker of tolerance to exercises, but also as one of the stress resistant indicator of the organism.