A 71-year-old man with exertional chest pain was admitted to the hospital. A chest roentgenogram exhibited levoposition of the heart. An electrocardiogram showed clockwise rotation in the precordial leads and ST depression in V6, V7, V8, and V9 as well as in II, III, aVF leads associated with chest pain in a treadmill exercise test. The congenital complete left-sided pericardial defect could not be diagnosed preoperatively, but it was confirmed by thoracotomy.