Here we performed individual evaluation of the oxidative stress index that serves as an integral criterion for the balance of LPO-antioxidant defense system in women with endocrine pathology (type 1 diabetes mellitus and infertility with hyperprolactinemia). The state of the LPO-antioxidant defense system was estimated from blood levels of LPO substrates with conjugated double bonds, conjugated dienes, ketodienes, conjugated trienes, thiobarbituric acid-reactive substances, retinol, α-tocopherol, reduced and oxidized glutathione, and SOD activity. The use of this oxidative stress index allowed us to diagnose oxidative stress in female patients with endocrine pathology.