For maintenance of physiological processes of spermatogenesis and steroidogenesis in testes and favorable microenvironmental conditions in tissues of epididymis during maturation, transport and storage of spermatozoa it is of crucial importance that antioxidative enzymes act properly in order to control physiological levels of reactive oxygen species. Further, acquisition of spermatozoa motility and fertile capability during transport through epididymis is associated with different biochemical changes particularly in characteristics of their cell membranes and corresponding molecular mechanisms, which are not fully defined yet. However, the ability of testes and epididymis to protect spermatozoa from detrimental effects of oxidation processes by locally synthesized antioxidants is not studied in details up to now. The aim of this study was to investigate differences in level of antioxidative protection, intensity of lipid peroxidation and values of biochemical parameters in testes and different parts of epididymis in reproductive mature boars. Besides, the correlation among tested parameters in different parts of reproductive system and spermatozoa of different stages of maturity were studied. Study was performed on 5 clinically healthy and reproductive mature boars of Swedish landrace breed aging 10 months. Tissue samples of testes and head, body and tail of epididymis were taken. In obtained supernatants of homogenized tissues the activity of glutathione peroxidase (GSH-Px), glutathione reductase (GSH-RD), superoxide dismutase (SOD), gamma glutamyl transferase (GGT), acid phosphatase and lactate dehydrogenase (LDH) as well as concentrations of triacylglycerols, phopsholipids, cholesterol, free fatty acids (FFA) and malondialdehyde (MDA) were determined. Significantly higher activities of GSH-Px and GSH-RD (P<0.05) were determined in tissue of testes as compared to those in tissues of epididymis. In tissue of testes it was established significantly higher activity of SOD in comparison to that found in tissues of head and tail od epididymis (P<0.05). Concentration of MDA in head of epididymis was significantly higher from that in testes, body and tail of epididymis but significantly lower than that in tissues of body and tail of epididymis as compared to that in testes (P<0.05). In tissue of epididymis tail significantly higher activities of GGT, ACP and LDH were recorded in relation to those in testes. Significantly lower concentrations of TAG and FFA were recorded in epididymis tail tissue in comparison to those in epididymis head tissue (P<0.05). From the obtained results it could be concluded that high activities of antioxidative enzymes in testes of boars are essential for appropriate protection of spermatozoa and cells of testes tissue against oxidative damages. The tissues of testes and epididymis head in boars were more susceptible to lipid peroxidation, i.e. to oxidative stress. A significant protective function has intracellular glutathione which is maintained by GGT against oxidative stress during storage of spermatozoa in epididymis tail. The results of current study indicate physiological importance of antioxidative enzymes in tissues of reproductive system in boars. Furthermore, the obtained results may serve for better understanding of mechanisms of male infertility and for improvement of boar semen storage.