The internal mammary artery (IMA) is being recognized as the conduit of choice for myocardial revascularization. From January 1972 through June 1988, 1,087 patients received bilateral IMA and supplemental vein grafts. There were 917 men (84.4%) and 170 women (15.6%) with a mean age of 62.4 years (range, 29 to 84 years). Three hundred ninety-four patients (36.2%) had unstable angina, and 194 (17.8%) had left main coronary artery stenosis greater than 50%. In all, 3,741 coronary grate were performed, with a mean of 3.4 per patient. Hospital mortality was 2.7%(29 patients). Hospital complications included reoperation for bleeding, 19 patients (1.7%); sternal infection, 16 patients (1.5%); respiratory failure, 35 patients (3.2%); perioperative myocardial infarction, 22 patients (2.0%); and stroke, 20 patients (1.8%). Postoperative arteriography in 53 patients (mean postoperative time, 53.0 months) showed that 92.1%(58/63) of the left IMA and 84.9%(45/53) of the right IMA grafts were patent. Follow-up was completed on 1,058 hospital survivors. There were 82 late deaths (7.8%). The actuarial survival for patients discharged from the hospital was 80.0%±3.2%(plus or minus standard error of the mean) at 10 years and 60.0%±5.0% at 15 yean. At follow-up, 866 patients (90.3%) were asymptomatic and in New York Hearl Association class I and 68 (7.1%) were in class II. This longitudinal analysis demonstrates that bilateral IMA grafting has a low operative risk and provides excellent long-term functional improvement and survival.