The present study was designed to investigate the cardioprotective effect of sodium nitrite (NaNO2) and sodium nitrate (NaNO3) against myocardial ischemia-reperfusion (I/R) injury in a pig regional ischemia model. Eighteen pigs were randomly divided into three groups as control (Group 1), sodium nitrite (Group 2) and sodium nitrate (Group 3) groups. Before the exploration of the heart, blood samplings were taken for alanine aminotranspherase (ALT), aspartate aminotranspherase (AST), lactate dehydrogenase (LDH), creatinine kinase-muscle band (CK-MB), troponin-t, glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA) and nitrite/nitrate (NO2-/NO3-) in all groups (T0). Following sternotomy and stabilization, blood and tissue samples were repeated (T1). Then, intracoronary sodium nitrite and sodium nitrate were given (0.5µg/kg) in Groups 2 and 3. Five minutes later, the left anterior descending (LAD) artery was ligated for I/R experiments. Blood and tissue samplings were repeated after 60 minutes of ischemia (T2) and 180 minutes of reperfusion period (T3). Light and electron microscopic investigations were performed. There were statistically significant results in favor of Group 2 in all studied parameters. Hemodynamic parameters showed a decrease in mean arterial pressure (MAP), cardiac output (CO), cardiac index (CI) and an increase in heart rate, mean pulmonary artery pressure (MPAP), left ventricle end-diastolic pressure (LVEDP), pulmonary capillary wedge pressure (PCWP) during ischemia. Following the ischemia these parameters returned to their near normal levels. This was prominent in group 2. Oxidative parameters showed protective increases in GPx, SOD, CAT and NO2-/NO3- levels and a decrease at MDA both in tissue and blood samples in group 2. There were statistical differences only in T3 for AST, troponin-t and CK-MB levels in favor of Group 2. Histological and electron microscopy examinations were also in favor of NO2- group. The results of the present study indicate that NaNO2 provides protection against myocardial I/R injury when compared to control and NaNO3 groups.