Chemoprevention has emerged as a very effective preventive measure against carcinogenesis. Many bioactive compounds present in edible as well in herbal plants have revealed their cancer chemopreventive potential. In the present study, our goal was to investigate the impact of piperine, a principle ingredient of pepper, on alterations of mitochondrial antioxidant system and lipid peroxidation in Benzo(a)pyrene (B(a)P) induced experimental lung carcinogenesis. Oral supplementation of piperine (50 mg/kg body weight) effectively suppressed lung carcinogenesis in B(a)p induced mice as revealed by the decrease in the extent of mitochondrial lipid peroxidation and concomitant increase in the activities of enzymatic antioxidants (superoxide dismutase, catalase and glutathione peroxidase) and non enzymatic antioxidant (reduced glutathione, vitamin E and vitamin C) levels when compared to lung carcinogenesis bearing animals. Our data suggests that piperine may extent its chemopreventive effect by modulating lipid peroxidation and augmenting antioxidant defense system.