Since the introduction of percutaneous; transluminal coronary angioplasty[PTCA] by Grunt-zig in 1977, this is widely used in some patients with coronary artery disease and is an effective alternative to surgery for many patients. Indications for emergency coronary artery bypass graft[CABG] after PTCA are prolonged chest pain, worsening of coronary artery obstruction, "current of injury" by electrocardiogram, cardiogenic shock, and in a lesser incidence, ventricular fibrillation, coronary artery dissection[without obstruction], heart block, and intractable cardiac arrest. Recently, we have experienced one case of emergency CABG following unsuccessful PTCA. The patient was 54 year-old male and admitted with complaint of angina pectoris. The routine electrocardiogram revealed within normal limit. The treadmill test revealed severe chest pain after 2 min. exercise. Coronary cineangiogram revealed 95% segmental stenosis of the proximal right coronary artery. Our cardiologist was planned PTCA. During PTCA, severe chest pain and ischemic pattern on electrocardiogram were developed. But they were not relieved even by morphine and nitroglycerin till 90 min. So we performed emergency single coronary artery bypass graft from aorta to proximal right coronary artery with great saphenous vein. The patient had an excellent postoperative recovery and was free from anginal attack. He has shown striking improvement in general status[NYHA functional class 1] during 6 months after operation.operation.