Background and Objectives : The coronary artery aneurysm, defined as a dilation of the coronary artery that exceeds 1.5 times the reference diameter of the adjacent coronary segments that are angiographically normal, has been reported after percutaneous coronary intervention. It was reported that coronary artery aneurysm was observed in 3.9% of the patients submitted to Palmaz–Schatz stent implant. But the incidence of drug eluting stent (DES)-related coronary artery aneurysmis currently not clear. Methods : We retrospectively reviewed the 800 patients and their follow-up angiography after DES insertion and analyzed 250 patients and 425 lesions found at Uijeongbu and Daejeon St��� Mary Hospitals between 2004 and 2008. Results : 29 lesions had developed neoaneurysm in their follow-up coronary angiography. There were more complex lesion, more CTO lesion, longer lesion, more overlapping stent and more frequently stent fracture in the neoaneurysm group(Table 1). Conclusion : Neoaneurysm had seen in the real practice world of DES era, but its clinical meaning will be discussed.