Objective We studied whether single high dose statin loading is beneficial on the outcome of patients with acute myocardial infarction(AMI) by reduction of myocardial damage and oxidative stress. Methods Consecutive 65 patients with AMI who underwent primary PCI were randomly assigned to three group; Group I(n=21): no statin treatment before PCI, Group II(n=22): 10 mg rosuvastatin loading before PCI, Group III(n=22): 40mg rosuvastatin loading before PCI. Periprocedural myocardial injury was assessed by peak level of creatinine kinase-MB(CK-MB). Baseline and follow up inflammatory markers, lipid level and thioredoxin level were also measured. Major adverse cardiac events (MACE; death, myocardial infarction, target lesion revascularization) were evaluated. Results There were no significant differences in clinical characteristics between the groups. Mean preprocedural creatine kinase (CK)-MB and high sensitivity C-reactive protein (hsCRP) showed no significant differences between the groups. After PCI, peak CK-MB level(388.7짹264.3 vs 403.7짹225.7 vs 193.7짹143.2 IU/L, respectively; p=0.04) and hsCRP level (24.3짹22.2 vs 19.3짹25.6 IU/L vs 3.2짹6.9 mg/dL, respectively; p=0.01) were significantly lower in in Group III. There were no significant differences in MACE between the groups during 6 months follow up. The oxidized LDL and thioredoxin level will be reported in October. Conclusions High dose of statin prior to PCI reduces periprocedural myocardial injury and inflammation in patients with AMI.