Background and Objectives竊�The first on-line registration of Korea Acute Myocardial Infarction patients (KAMIR) has been carried out throughout the 41 primary percutaneous coronary intervention (PCI) centers that are supported by the Korean Circulation Society (KCS), as reported in the memorandum of the 50th Anniversary of the KCS. Little data exist concerning the clinical outcome of patients with acute myocardial infarction (AMI) with angiographically non-significant stenosis. The purpose of this study was to evaluate the clinical outcome of these patients. Subjects and Methods竊�Between Nov 2005 and Dec 2006, 8566 patients were enrolled in KAMIR and 2295 eligible patients (1625 males and 670 females; mean age=64.3짹12.4 years) were analyzed for one-year clinical follow-up. The clinical outcome for acute myocardial infarction (AMI) was analyzed according to angiographic findings (significant stenosis group vs. non-significant stenosis group). Results竊�The percentages of smoking, hyperlipidemia and hypertension were similar between the two groups, but higher prevalence of diabetes was observed in non-significant stenosis group (p<0.0001). CK-MB and troponin- I were less elevated and NSTEMI presentation is more common in non-significant stenosis group (p<0.0001, p<0.0001, p<0.0001). One-year clinical outcomes with re-AMI, re-PCI, CABG, cardiac death, non-cardiac death are less commonly observed in non-significant stenosis group (285/2182 vs. 5/113, p<0.0001). Conclusion竊� AMI patients with angiographically non-significant stenosis are associated with higher event free survival compared to patients with significant stenosis.