Background and Objectives: Late or very late stent thrombosis after drug-eluting stent (DES) implantation may be related with incomplete neointimal coverage. Optical coherence tomography (OCT) is valuable modality for the assessment of stent strut coverage. We evaluated long-term (2 years) effect of everolimus-eluting stent (EES) for tissue coverage and apposition of stents using OCT compared with 9 months follow-up results. Subjects and Methods: OCT was evaluated in 30 EESs (28 patients) diagnosed as acute coronary syndrome. The percent difference of uncovered struts was analyzed according to follow-up period (9 month vs. 2 year). Results: Group I (short-term group, 22 lesions in 21 patients) and Group II (long-term group, 8 lesions in 7 patients) were included in the analysis. The stent diameter and stent length were no significant differences in both groups (2.94 짹 0.35 vs. 3.06 짹 0.28, p=0.398; 24.27 짹 8.28 vs. 31.13 짹 13.00, p=0.097, respectively). The area of neointimal coverage was significantly higher in Group II (11.5 짹4.1 vs. 18.5 짹 5.9, p=0.012) and the percent of uncovered struts was significantly reduced in Group II (9.7 짹 7.0 vs. 3.0 짹 5.2, p=0.019). No differences was shown in malapposed stent struts between both groups (3.2 짹 8.8 vs. 0.8 짹 1.8, p=0.441). Conclusions: Frequent incomplete neointimal coverage was still observed even in new generation stent (EES) at 9 months. But, uncovered stent struts were significantly reduced at 2 years follow-up. Further studies are required to determine the clinical significance of this finding.