Emergent coronary artery bypass grafting (CABG) for the treatment of acute coronary syndrome has increased the operative mortality. Forty-nine patients underwent urgent or emergent CABG for the treatment of medically refractory unstable angina in 10 patients, and for acute myocardial infarction (AMI) in 39 patients. Ten operative deaths were occurred in the AMI patients, and the mortality was 20 percent. The preoperative risk factors were evaluated in 10 patients who died in the operative period. Cardiopulmonary resuscitation before operation, intra aortic balloon pumping, the use of catecholamine, and intubation with or without percutaneous cardiopulmonary support revealed operative risk factor. Because the patients who have preoperatively shock, it seemed to be needed that the rescue of the patients should improve the clinical results for urgent or emergent CABG.