Of the 318 patients surviving the first postoperative month 14 died secondarily, 5 were lost to follow-up, and 299 were therefore reviewed with a mean follow-up of 16.6 months (extremes of 2 and 42 months). The percentage of late infarcts was 5.9%. Complete disappearance of the angina occurred in 80.3% of patients. Persistant angina was commoner in females (p less than 0.05) and in patients with a lesion affecting all three trunks (p less than 0.05). On the other hand age, the clinical indications for bypass, the presence of an infarct preoperatively, and the development of an infarct immediately postoperatively did not affect the functional result. The cardio-thoracic ratio decreased significantly, from0.51 +/- 0.07 to 0.47 +/- 0.05 (p less than 0.001). 45 coronary arteriograms in a total of 63 grafts were analysed. 73% were patent after a follow-up period of 10.5 months. The patency rate was 88.6% when coronary arteriography was carried out systematically, and 63% (p less than 0.002) when it was indicated by persistant or recurrent angina. The actuarial survival curve in patients with 2 or 3 trunk involvement demonstrates clearly the superiority of surgical over medical treatment.