Surgical angioplasty of the left main coronary artery confers several advantages over conventional bypass surgery: unrestricted forward flow is provided to the entire coronary bed and graft material is spared. The literature contains many reports of surgical angioplasty of atherosclerotic stenoses. The technique is described in five patients with non-atherosclerotic disease of the left main coronary artery: three children (a 7 year old girl who had undergone an arterial switch operation shortly after birth; a 9 year old boy with congenital supravalvar aortic stenosis; and a 10 year old girl with Kawasaki's disease) and two adults (a 51 year old woman with post-radiation stenosis; a 53 year old man with acute dissection). All patients had an uneventful recovery and are free from symptoms with a widely open left main trunk. Although technical difficulties are increased in these patients, excellent results can be achieved with this approach.