BACKGROUND AND OBJECTIVES: Coronary artery perforation is a rare, but potentially deadly, complication of percutaneous coronary intervention (PCI). The purpose of this study was to analyze the clinical characteristics, and outcome, of coronary artery perforation. SUBJECTS AND METHODS: We retrospectively reviewed 3,782 consecutive PCIs, performed between January, 1994 and May, 2002 at the Samsung Medical Center, from the database records. The medical records and angiograms of the patients were also reviewed. The coronary artery perforations were classified according to Ellis' classification. RESULTS: A coronary artery perforation was noted in 24 patients (0.6%). It was most commonly observed during PCI of the right coronary artery (46%) and a chronic total occlusion intervention (42%). The number of the patients with Ellis'classes I, II and III were 11, 8 and 5, respectively. The most frequent causes of the perforation were guidewire, followed by balloon (11 and 8 cases, respectively). The interventional modality with the highest risk of perforation in this study was rotational atherectomy, (4 out of 157, 2.6%). Five patients had cardiac tamponade, of which four occurred during a rotablator procedure. Pericardiocentesis was performed in 5 patients, while 3 patients with class III perforations received emergent coronary artery bypass surgery. There were no in-hospital mortalities, although the duration of the hospital stay for the class III patients was longer than those with classes I or II perforations. CONCLUSION: A coronary artery perforation during percutaneous coronary intervention is a potentially serious complication. However, the immediate and adequate management results in a fairly good prognosis.