One patient developing left main coronary stenosis following double valve replacement is reviewed. Angina pectoris developed 5 months postoperatively. Coronary perfusion with a balloon tip perfusion catheter was performed during previous operation and was considered technically satisfactory. Coronary angiography confirmed stenosis of the left main coronary artery. There was no further coronary arterial disease. An anterior approach between the aorta and pulmonary artery to expose the left main coronary artery was used and patch angioplasty was done. Repeat coronary angiography showed a widely patent left main coronary artery with excellent runoff. A careful search for coronary arterial injury should be made in all symptomatic patients following aortic valve replacement.