Background : Intravenous nicorandil infusion with percutaneous coronary intervention (PCI) has been reported to reduce reperfusion injury events and improve cardiac function in patients with an acute myocardial infarction. A prospective randomized single center study was designed to evaluate the efficacy of intra-coronary nicorandil. Methods : Seventy-three patients with acute ST segment elevation myocardial infarction were randomly assigned to the nicorandil group (n=37) or a control group (n=36); all patients had a PCI. In the nicorandil group, 4 mg of intra-coronary nicorandil was infused directly into the infarct area prior to reperfusion (2 mg before ballooning, 2 mg before stenting). Results : The baseline characteristics were similar in both groups. A significant difference was observed in the primary study endpoint in the nicorandil group compared to the control group (p=0.037). The post TIMI grade 3 was significantly higher in the nicorandil group (p=0.019). The myocardial blush grade 1 was not observed in the nicorandil group; however, it was observed in five patients in the control group (p=0.019). Conclusion : Intra-coronary nicorandil infusion reduced the occurrence of no reflow, slow reflow, reperfusion arrhythmia and improved the myocardial brush grade and TIMI flow during PCI.