The current study dealt with the protective role of mangiferin, a polyphenol from Mangifera indica Linn. (Anacardiaceae), on isoproterenol (ISPH)-induced myocardial infarction (MI) in rats through its antioxidative mechanism. Subcutaneous injection of ISPH (200 mg/kg body weight in 1 ml saline) to rats for 2 consecutive days caused myocardial damage in rat heart, which was determined by the increased activity of serum lactate dehydrogenase (LDH) and creatine phosphokinase isoenzymes (CK-MB), increased uric acid level and reduced plasma iron binding capacity. The protective role of mangiferin was analyzed by triphenyl tetrazolium chloride (TTC) test used for macroscopic enzyme mapping assay of the ischemic myocardium. The heart tissue antioxidant enzymes such as superoxide dismutase, catalase, glutathione peroxidase, glutathione transferase and glutathione reductase activities, non-enzymic antioxidants such as cerruloplasmin, Vitamin C, Vitamin E and glutathione levels were altered in MI rats. Upon pretreatment with mangiferin (100 mg/kg body weight suspended in 2 ml of dimethyl sulphoxide) given intraperitoneally for 28 days to MI rats protected the above-mentioned parameters to fall from the normal levels. Activities of heart tissue enzymic antioxidants and serum non-enzymic antioxidants levels rose significantly upon mangiferin administration as compared to ISPH-induced MI rats. From the present study it is concluded that mangiferin exerts a beneficial effect against ISPH-induced MI due to its antioxidant potential, which regulated the tissues defense system against cardiac damage.