Background: Nicorandil has been reported as a hybrid ATP sensitive potassium channel (K+ATP channel) opener and nitric oxide donor. It has additive effect on myocardial microcirculation and cardiac function. We investigated the effect of nicorandil use during percutaneous intervention on myocardial perfusion, myocardial injury, and cardiac function in patients with myocardial infarction(MI). Subject and Method: We analysed 719 consecutive patients who underwent percutaneous intervention due to myocardial infarction including acute ST elevation MI, non-ST elevation MI, and recent MI from Jan. 2001 to July 2004. While patients in case group (n=344) had been administrated nicorandil intravenously with dose of 6mg/hr for 48 hours from just admitted time simultaneously with isosorbide dinitrate, patients in control group (n=375) had been taken isosorbide dinitrate only. During intervention, 2 mg of nicorandil was additively infused by intracoronary bolus administration before stenting. We compared the coronary blood flow, myocardial perfusion grade, abxicimib use, echocardiographic myocardial function, 30 day MACE. Results: There were no differences in basal clinical data between two groups. Decreased coronary blood flow after stenting was developed in 42 patients (12.2%) of case group, and in 57 patients (15.2%) of control group (p<0.01). Abxicimab was administrated to intractable cases of ���No reflow��� in 10 patients (2.9%) of case group, and in 21 patients (5.6%) of control group (p<0.01). Myocardial perfusion grades were significantly higher in case group than control group (1.71짹0.55 vs 1.40짹0.79, p<0.05) among patients with decreased coronary flow. LVEF and E/A ratios were significantly higher in case groups. 30 day MACE was significantly lower in case group than in control group (2.6 vs 4.3%, p<0.05). Conclusion: We conclude that intravenous nicorandil additionally attenuates ischemic microvascular damages and thereby provides functional and clinical outcomes.