Background: There has been limited data regarding the late clinical impact of post-procedural incomplete stent apposition (PISA) and late incomplete stent apposition (LISA) in the newer generation of drug eluting stent. The aim of this study was to investigate the incidence of LISA and change of PISA during follow up. Methods: We prospectively enrolled 101 patients who underwent percutaneous coronary intervention (PCI) in de novo coronary lesions; stable angina (n=26), unstable angina (n=61), and non-ST segment elevation myocardial infarction (n=13) (62.2짹8.8 years, 72 male, 121 lesions). The group was randomly assigned (proportion of 2:1) to zotarolimus eluting stent (group I, n=81, Endeavor ResoluteTM, Medtronic, MN) or everolimus eluting stent (group II, n=40, XienceTM V, Abbott Vascular, Illinois). Post-PCI and follow up intravascular ultrasound (IVUS, mean 9.9짹2.4 months) were performed in all patients. Results: The Post-PCI external elastic membrane (EEM) volume (group I vs group II, 417.3짹196.5 vs 409.7짹180.1 mm3, p=NS), post-PCI lumen volume (228.6짹111.0 vs 223.0짹89.5 mm3, p=NS), follow up EEM volume (435.1짹168.1 vs 414.9짹179.4 mm3, p=NS), and follow up lumen volume (236.6짹91.7 vs 222.5짹90.1 mm3, p=NS) by IVUS were not different between the two groups. There were three LISAs [2.5%, group I (n=2) vs group II (n=1)] and thirty four PISAs [8.1%, group I (n=23) vs group II (n=11)] that were resolved [14.7%, group I (n=4) vs group II (n=1)]. Post-PCI and follow up volume of PISA was not significantly different in both group I (5.9짹5.6 vs 5.1짹4.6 mm3, p=NS) and group II (8.9짹4.4 vs 8.5짹4.2 mm3, p=NS). There was no major adverse cardiac event associated with LISA or PISA during 12-month clinical follow up. Conclusions: In conclusion, the incidence of LISA was very low in both groups. Both LISA and PISA were not associated with cardiac events during 12-month follow up. Future long-term follow up study to clarify the clinical course of LISA and PISA would be needed to confirm our results.