A 67-year-old male patient had coronary artery bypass graft. Before the induction of general anesthesia, 16 gauge central venous catheter was inserted via left subclavian vein. Initial chest anteroposterior (AP) radiograph showed adequate position, and the central venous pressure measurement through it was satisfactory. This patient's progress was satisfactory, and he was extubated on the second postoperative day. Daily chest AP radiograph had been unremarkable until the third postoperative day, when a right-sided pleural effusion was seen. A day later, the patient complained severe chest pain and dyspnea. We suspected perforation of superior vena cava wall by tip of central venous catheter on the chest computerized tomograph (CT). The injection of radiopaque dye through the central venous catheter confirmed spillage into the mediastinum on the chest CT. Right chest tube was inserted. The patient's condition dramatically improved after chest tube insertion.