Introduction. There are evidence that oxidative stress is involved in the pathogenesis of the acute generalized peritonitis and diabetes mellitus.The aim of study was to examine levels of the products of lipid peroxidation and the antioxidants in rats with experimental acute generalized peritonitis against the background of streptozotocin-induced diabetes.Material and methods. The experiment was performed on 66 adult white male rats weighing 220-300 g. Diabetes mellitus in experimental animals was simulated by a single intraperitoneal injection of streptozotocin (Sigma) at the dose of 60 mg/kg. Acute generalized peritonitis was induced with 10% faecal suspension in a dose of 0.5 ml per 100 g of animal weight in the abdominal cavity of laboratory animals by puncture method. The thiobarbituric acid reactive substances (TBARS), lipid hydroperoxides (LOOHs), superoxide dismutase (SOD) activity, catalase (CAT) and ceruloplasmin (CP) were estimated and compared.Results. Our results showed that during all stages of development of acute generalized peritonitis on the background of streptozotocin-induced diabetes there is the LOOHs decrease and the TBARS increase. We observed statistically significant inverse correlations between the level of LOOHs and SOD in the animals of subgroup 1 (r = -0.88; p <0.05) and inverse correlations between the TBARS level and the SOD level in the subgroup 3 of animals (r = -0.74; p <0.05). We also found a statistically significant inverse correlation between the CAT level and the TBARS level (r = -0.86; p <0.05) and between the CP level and the TBARS level in the blood of animals in the subgroup 3 (r = -0.87; p <0.05).Conclusion. Negative statistically significant correlations between the TBARS level and the antioxidants (SOD, CAT, CP) in the blood of animals with acute generalized peritonitis on the background of streptozotocin-induced diabetes indicate a predictor role of lipid peroxidation processes in the depletion of antioxidant resources