In the recent years, laser has been widely utilized in the field of medicine. But, there are few application in the cardiovascular surgery. Since 1980, we have applied lasers in the following three categories in the field of cardiovascular surgery. That is, Group 1: laser angioplasty for occlusive arterial disease, Group 2: laser vascular anastomosis especially for small caliber vessels, Group 3: new myocardial revascularization. Consequently, effects of laser application could be clearly recognized in these fields. On the basis of excellent results of our experimental studies, laser was clinically employed for 135 patients with anginal pain, intermittent claudication or renal failure. Optimal conditions for laser angioplasty were 6 watts in output and 3 sec in irradiation time for each shot. Laser irradiation was carefully repeated according to the grade of atherosclerotic changes. Angioscope was useful for keeping safe procedures. On the other hand, optimal conditions of vascular anastomosis were 20-40 mW in output and 6-12 sec/mm in irradiation time. They consisted of laser angioplasty with 6 cases of intraoperative coronary laser angioplasty in 37 cases, and vascular anastomosis including 8 cases of coronary artery bypass surgery in 97 cases, new myocardial revascularization in one case. These patients are doing well without any complications throughout laser. Our clinical experience of laser application in the cardiovascular surgery are presented.