Objectives and backgrounds: The technique of percutaneous coronary intervention(PCI) involving chronic total occlusion(CTO) has improved over time. However, acute and follow-up results in CTO patients treated with PCI are limited in Korea. Methods: One hundred fifty six patients who underwent PCI for CTO were enrolled from Jan 28, 2000 to Dec 31, 2003. Among them, 14 patients were excluded (9: CABG, 3: lost to follow up, 2: death from cancer). The remaining 142 patients were divided into two groups according to successful revascularization(group A: those with successful revascularization, n=88 , group B: those without successful revascularization, n=54). Major adverse cardiac events(MACE; cardiac death or nonfatal myocardial infarction) and Total adverse cardiac events (TACE ; cardiac death, non-fatal myocardial infarction, readmission or coronary artery bypass graft for recurrent ischemic chest pain) were compared between the two groups, retrospectively. Results: The patients were followed up for a mean of 687짹415 days after initial coronary angiography ; 5 patients died in group B(p=0.0007). Late nonfatal MI occurred in 6 patients (5 patients in Group B and 1 patient in Group A(p=0.03).The TACE rate was 17.0% for group A(15/88) versus 39%(21/54) for group B(p=0.004). On multivariate analysis, the only variable associated with TACE free survival was the successful revascularization of CTO Conclusion Successful recanalization of CTO by PCI improved long term clinical outcome.