The aim of the present study was to investigate the chemopreventive effect of coumarin against 7,12-dimethylbenz[a]anthracene (DMBA)-induced hamster buccal pouch carcinogenesis by monitoring tumorincidence and histopathological changes as well as by analyzing the status of biochemical markers (lipidperoxidation, enzymatic and non-enzymatic antioxidants, phase I and phase II detoxification enzymes). Oralsquamous cell carcinomas were induced in the buccal pouch of Syrian golden hamsters by painting with 0.5%DMBA in liquid paraffin three times a week for 14 weeks. We noted 100% tumor formation with markedabnormalities in the biomarkers status in hamsters treated with DMBA alone. Oral administration of coumarinat a dose of 100 mg/kg body weight (bw) to DMBA treated hamsters completely prevented the tumor formationas well as restored the staus of biochemical variables. The results of the present study thus suggest that thechemopreventive effect of coumarin is probably due to its anti-lipid peroxidative potential and modulating effecton carcinogen detoxification agents in favor of the excretion of ultimate carcinogenic metabolites of DMBAduring DMBA-induced hamster buccal pouch carcinogenesis.