Insulin-dependent diabetic (IDDM) patients with end-stage renal disease and coronary artery stenoses > or = 75% have a poor prognosis. However, information is lacking on the morbidity and mortality of the coronary artery bypass operation in this group. We studied 30 consecutive IDDM transplant candidates undergoing a bypass operation to determine the incidence of complications and long-term outcome. Perioperative mortality was 3% and the complication rate was 60%. During follow-up, five patients experienced six myocardial infarctions, the majority within six months of operation. Twenty-one patients underwent successful kidney transplantation after the bypass operation. Overall patient survival was 80%, 73%, and 66% at 1, 2 and 4 yr. In summary, the coronary artery bypass procedure in IDDM transplant candidates has a high morbidity, but the long-term outcome is good. Appropriately counseled IDDM transplant candidates with coronary artery disease should be considered for coronary revascularization and subsequent transplantation.