The aim of the study. In the process of their vital activity, the cells are exposed to many damaging factors of endogenous and exogenous nature. It is undoubtedly that various toxic influences or metabolic disorders lead to the development of oxidative stress, and in this case the future of the cell is determined by a balance of various adaptive metabolic processes induced by a pathological factor, as well as by genetic and constitutional features of its biochemical systems. The aim of the study was to analyze the mechanisms of caspase-dependent apoptosis and pro- and antioxidant activity in the thyroid tissue homogenate in patients with NGAIT and TA considering the polymorphic variants of BCL-2 (rs17759659), CTLA-4 (rs231775), APO-1 / Fas (rs2234767) genes. Material and methods. We investigated pro- and antioxidant activity and the activity of caspases 3 and 8 in 5% of thyroid tissue homogenates. The BCL-2 (rs17759659), CTLA-4 (rs231775), Fas (rs2234767) genes polymorphism were studied by Real-Time Polymerase Chain Reaction in 95 patients with NGAIT, 30 patients with TA and 25 healthy individuals. Results. We have not found any pronounced dependence of the processes OMP and AOP, nor the activity of caspases-8 and 3 in the thyroid tissue on the genotypes of BCL-2 (rs17759659) and APO-1/Fas (rs2234767) genes. However, it should be noted that in homozygous carriers of A-allele of the BCL-2 (rs17759659) gene, the activity of effector caspase-3 is higher than in the control group. Conclusions. The imbalance between the activity of peroxidation and antioxidant defense in patients with NGAIT and TA is associated with the promoter of the CTLA-4 (rs231775) and APO-1 / Fas (rs2234767) genes and is characterized by an increasing degree of OMP in the altered thyroid tissue, alongside with a lower capacity of the AOP system enzymes. Abbreviations: NGAIT - nodular goiter on the background of autoimmune thyroiditis; TG thyroid gland, TA – thyroid adenoma, OMP - oxidative modification of proteins, AOP – antioxidant protection.