BACKGROUND: Coronary perforation is a rare but potentially life-threatening complication during percutaneous intervention. Recent reports have shown that the coronary perforation in the general interventional population is 0.1% to 0.6%. The purpose of the present study is to report the incidence and clinical outcomes of coronary perforations occurring in patients undergoing PCI. METHODS: In this study we have analysed the retrospectively recorded procedural data on all patients attending the Catholic University Medical College affiliated hospital of Korea for PCI between January 1, 2005, and July 31, 2007. RESULTS: A total of PCI procedures were performed 4947 patients. Twelve cases of coronary perforations were identified, with an overall incidence of 0.24%. The target lesions were located in the left main coronary artery in 1 patient, the left anterior descending artery in 6, in the left circumflex artery in 1, and in the right coronary artery in 4 patients. The angiographic characteristic of the target lesion was type B1 in 3 patients, type B2 in 2 patients, and type C in 7 patients. Mean lesion length was 32.4 mm. 10 patients(in 5 patients with cypher and in 5 patient with Taxus) underwent drug-eluting stent implantation. 1 patient underwent implantation of a bare-metal stent. When perforation was confirmed, pericardiocentesis was performed in 6 patients. Reversal of heparin with protamine sulphate was performed in 3 patients. Restoration was attempted by immediate balloon occlusion in 3 cases, implantation of a covered stent graft in 3, coil embolization in 1, and emergency surgical repair in 1 case. Two patients(16.7%) died. CONCLUSION: In the era of drug-eluting stent implantation, the incidence of coronary perforation has been increasing. Especially it occurs more frequently with long segment stent implantation. Particular caution should be exercised in patients with long lesion PCI.