Background: Coronary artery aneurysm (CAA) is a complex complication of drug-eluting stent (DES), which may be associated with stent thrombosis and in-stent restenosis (ISR), with varying clinical presentations. However, its natural fate and long-term clinical outcomes are unknown. Methods: From the percutaneous coronary intervention registry with drug-eluting stent, 35 consecutive patients between 2004 and 2008 were adjudicated to have coronary artery aneurysm in our previous study. Of 35 patients, 29 CAAs in 28 patients who underwent 2-year angiographic follow-up after the first detection of CAAs were analyzed. A CAA was defined as a localized dilatation exceeding 1.5 times in diameter of the adjacent artery. Major adverse cardiac events (MACE) were determined, including cardiac death, myocardial infarction (MI), target-lesion revascularization (TLR), and target-vessel revascularization (TVR). Results: Follow-up duration was 838짹381 days. Although 22 patients (78.6%) remained asymptomatic, MACEs were found in 10 patients (35.7%). No cardiac death occurred. Non-fatal myocardial infarction occurred in 1 patient (3.6%), and was combined with very late stent thrombosis. TLR occurred in 9 patients (32.1%), and of which stable angina were presented in 5 patients and silent ischemia in 4 patients. Conclusions: Most patients with CAAs after DES implantation remained asymptomatic (78.6%) in this study, but some were presented with various clinical manifestations including acute myocardial infarction due to very late stent thrombosis and stable angina. Further investigations including very long term clinical and imaging follow-up are required to see natural course of CAAs. Key Words: Drug-eluting stent, Coronary aneurysm