Between October 1985 and September 1991, 400 patients benefited from bilateral internal mammary artery (BIMA) grafting. Of these, 354 (88.5%) were male and the average age was 57.4 years. There were 132 (33%) urgent procedures, 55 in diabetic patients (14%) and 15 in end-stage renal failures (4%). An average of 3.9 distal anastomoses (AN) per patient was undertaken, 2.8 using arterial grafts. Two hundred sixty-nine patients (67.2%) received exclusively arterial grafts. Right internal mammary artery (RIMA) grafts were predominantly directed to the left coronary system (348 AN = 78%) and particularly to the circumflex (CX) area. Postoperative myocardial infarction was diagnosed in 16 patients (4%). Reoperation was required for early myocardial ischemia in 12 patients (3%) and for excessive bleeding in 23 patients (5.8%). Sternal complications occurred in 18 patients (4.1%), 5 in diabetic patients (9%) and 3 in renal patients (20%). The hospital mortality was 2% (8 patients, 3 cardiac causes). Follow-up averages 37.7 months. Late mortality was 3% (12 patients, 4 cardiac causes). Angina recurred in 12 patients (3.1%). The maximal stress test at a mean interval of 9 months was abnormal in 7.4% (21 patients). One hundred eighty-one patients (47%) consented to an angiographic restudy at an average of 13 months postoperatively. Pedicled RIMA patency rates equal those of pedicled LIMA (95.1 vs 96.7, NS) and the grafted vessel does not alter the patency rates of IMA AN. A pedicled IMA graft is preferable to a free IMA graft (96.1 vs 79.6, P < 0.001). The early patency rates of free IMA grafts and of saphenous grafts do not differ significantly (79.6 vs 84.7, NS): The former reflect the delicacy of the proximal AN and should subsequently behave similar to those of the pedicled AN grafts. Bilateral internal mammary artery grafting is expected to maintain excellent results over the long-term on the condition that it rests on reasonable indications and a thoughtful operative strategy.