Thioacetamide (TAA) exerts hepatotoxic, neurotoxic and carcinogenic effects. The aim of our study was to investigate the effects of TAA on lipid peroxidation and catalase activity in various rat brain regions. Male Wistar rats were divided into following groups: 1. control, saline-treated; 2. thioacetamide-treated groups, TAA300 (300 mg/kg), TAA600 (600 mg/kg) and TAA900 (900 mg/kg). Daily dose of TAA (300 mg/kg) was administered intraperitoneally once (TAA300), twice (TAA600) and three times (TAA900) in consecutive days. Brain samples were collected 24 h after the last dose of TAA and malondialdehyde (MDA) level and catalase activity were determined in cortex, brainstem and hippocampus. MDA level was significantly increased while catalase activity was significantly lower in all brain regions in TAA900 group in comparison with control group. In TAA600 MDA level was increased in the brainstem and cortex when compared to control (p < 0.01). The same dose of TAA 600 mg/kg induced a significant decline in catalase activity in the brainstem and cortex and an increase in its activity in the hippocampus when compared to control (p < 0.01). In TAA300 an increase in MDA level was evident only in the brainstem. Catalase activity was significantly higher in the cortex and hippocampus in TAA300 group in comparison with control (p < 0.01). Based on these results, it may be concluded that various rat brain regions have different sensitivity to TAA-induced lipid peroxidation with hippocampus being less sensitive than cerebral cortex and brainstem.