The effect of chronic cigarette smoking on lipid peroxidation and antioxidant status in 100 newly diagnosed patients with gastric cancer was studied. Equal number of age- and sex-matched healthy control subjects was taken as control. The level of plasma and erythrocyte thiobarbituric acid reactive substances (TBARS) was markedly increased in both the gastric cancer patients when compared to control subjects. The activities of enzymatic and non-enzymatic antioxidants were significantly decreased in both (smokers and non-smokers) gastric cancer groups when compared to control subjects. Comparatively, the increased TBARS level and decreased antioxidants level was observed in smokers than non-smoking gastric cancer patients.