BACKGROUND : There is insufficient data on incidence of coronary artery aneurysms (CAA) and risk factor after drug-eluting stent (DES) implantation. METHODS: We analyzed 1167 consecutive patients who underwent follow-up angiography after DES implantation. Angiographic and clinical risk facors for new coronary aneurysm were anylized. RESULTS: Mean follow up duration was 3.46 years. Overall 26 CAAs (2.2% per patient) in 1167 patients were detected at follow-up, and the mean elapsed time from DES implantation to CAA diagnosis was 3.1짹1.3years. Clinically, CCAs developed more in non-ST elevation myocardial infarction (NSTEMI) (7.2% vs 1.8%). Angiographic predictor was log lesion(34.4 짹 20.8 mm vs 24.8 짹 12.0 mm, p<0.001; CCAs vs non-CAAs respectively, P=0.004). Procedual factor for CAAs was long stent implantation (36.3 짹 24.1 mm vs 27.8 짹 13.6 mm, p<0.001). Regression analysis revealed only NSTEMI and long lesion were independent predictor of CAAs develop after DES implantatioin. There was no significant diffrence in major adverse cardiac events(MACE) and stent thrombosis between CAAs and non-CAAs. CONCLUSION: NSTEMI was clinical predictor for CAAs occur and lesion length and long stent implantation was the angiographic and procedual predictor of CAAs after DES implantation. CAAs had favorable clinical outcome in terms of MACE and stent thrombosis.