Gray dormouse (Glis glis L.) is an autochthonous small game from the order of rodents, family of dormice. Metabolism of the dormouse is very intense during spring and summer, they mate, give birth to their young and feed intensively to prepare for hibernation. Under physiological conditions, production of reactive oxygen species and other molecules that cause oxidation in the body and the concentration / activity of antioxidant molecules are in equilibrium and depend on the intensity of metabolic processes. Therefore, the aim of this study was to determine activity of the enzymes glutathione peroxidase (GSH-Px), paraoxonase 1 (PON1) and superoxide dismutase (SOD), concentration of non-enzymatic antioxidant molecules using biological antioxidant potential (BAP) and the concentration of reactive oxygen metabolites (d-ROM) in liver, kidney, heart, and muscle tissue of female and male gray dormice just before hibernation. The study was conducted on the tissues of 33 individuals of gray dormice, of which 18 were females and 15 males. Samples were collected during the legal hunting season (September - October 2017). The highest activities of GSH-Px and PON1 were found in the liver tissue while the lowest activity was recorded in the gluteus tissue of the gray dormouse. No significant difference was found among genders in the studied tissues (p> 0.05). The highest SOD activity was found in kidney tissue, and the lowest activity was recorded in gray dormouse heart tissue. SOD activity did not differ significantly in the studied tissues in females and males of gray dormouse (p> 0.05). The highest concentration of BAP was recorded in gluteus tissue, while the lowest concentration was found in gray dormouse heart tissue. No statistically significant difference was found in values in females and males in the researched tissues (p> 0.05). The highest concentration of d-ROM was found in liver tissue, and the lowest in gray dormouse heart tissue. Concentration of d-ROM in gluteus and heart was significantly higher in males compared to females (p <0.05) while the concentrations in liver and kidneys were approximately equal. Based on the results, it can be concluded that oxidative and antioxidant processes are most intense in liver and kidneys, which corresponds to the intensity of metabolic processes in these tissues. The highest concentration of BAP in the gluteus muscle with the lowest activity of antioxidant enzymes indicates a compensatory effect of non-enzymatic antioxidant molecules. More intense oxidative processes in the heart of males confirm that males have a higher heart rate and in the m. gluteus indicate greater muscle activity compared to females of gray dormouse. Absence of a higher number of significant differences can be explained by the fact that the individuals in this study were hunted in September-October, ie at a time when the largest specimens of this species are already in the den, they are younger, lighter in mass individuals that are probably not yet reproductively mature.