In the past 20 years, basic and clinical research have provided new information on coronary artery surgery. For example, several studies have shown that coronary artery bypass grafting is more effective than medical treatment in relieving the symptoms of chronic disabling angina pectoris. However, we still do not have definitive answers to many questions. What factors in the patient, in the operation and in the care after operation determine success in surgical treatment? Does the operation prolong useful life? Is the operation affordable? These questions are difficult. Further research is needed to solve complex problems relating to surgical vs medical treatment of coronary artery disease.