Background: Coronary perforation (CP) is a rare, but sometimes lethal, complication of percutaneous catheter intervention (PCI). We reviewed surgically-treated cases of type 3 CP during PCI. Methods and Results: From 2007 to 2010, 5 patients underwent surgical repair for type 3 CP (3 men, 2 women; mean age, 74 years). The mean number of diseased coronary branches was 2.6 and the mean SYNTAX score was 45. The target lesions were the left anterior descending artery in 4 cases and the right coronary artery in 1 case. Types of American Heart Association/American College of Cardiology classification were type B2 in only one case and type C in 4 cases. The causes of perforation were balloon inflation in 4 patients and rotational atherectomy in 1 patient. The in-hospital mortality rate was 20%. In the cases of CP associated with balloon inflation, coronary lacerations were so severe that re-bleeding occurred even if the covered stent could temporarily achieve hemostasis, and percutaneous cardiopulmonary support and emergency surgery were required. Conclusions: CP induced by balloon inflation tends to result in a serious condition compared with rotablator-induced CP. Surgery should be immediately performed even after covered stent implantation if there is any possibility of re-bleeding in the case of balloon-induced type 3 CP. (Circ J 2012; 76: 377-381)