The aim of the present study was to evaluate the effect of the aqueous extract of seeds of two varieties, namely a country and hybrid variety of Momordica charantia (MCSEt1 and MCSEt2) on oxidative stress in plasma and pancreas of streptozotocin (STZ) induced diabetic rats. Oral administration of each of the seed extracts at a dosage of 150 mg/kg body weight for 30 d resulted in a significant reduction in plasma glucose, thiobarbituric acid-reactive substances, lipid-hydroperoxides, alpha-tocopherol and significant improvement in ascorbic acid, reduced glutathione and insulin. The treatment also resulted in a significant reduction in thiobarbituric acid reactive substances, lipid-hydroperoxides, superoxide dismutase, catalase, glutathione peroxidase and significant improvement in reduced glutathione in pancreas of drug treated diabetic rats when compared to the untreated diabetic rats. On the basis of results obtained, it may be concluded that the treatment of Momordica charantia seed varieties may effectively normalize the impaired oxidative stress in streptozotocin induced-diabetes than the glibenclamide treated groups.