The erythrocyte levels of the antioxidant enzymes SOD and GPx, and serum levels of antioxidants vitamins beta-carotene and beta-tocopherol were estimated in various types of brain tumors, and were compared with the levels in controls. Statistically significant (P<.001) diminished levels of beta-carotene, beta-tocopherol, SOD and GPx, were observed in all the brain tumor patients as compared to controls. Malignant tumor also showed a relative decrease in antioxidant levels as compared to benign tumors. Comparison of histopathological sections of brain tumors also suggested a inverse relationship between antioxidant level and grades of malignancy. Marked decrease in antioxidant levels may have a role in genesis of considerable oxidative stress in brain tumors. Furthermore, the degree of decline in antioxidant levels may indicate severity of malignancy in brain tumors.