Experience with 184 patients undergoing internal mammary artery bypass grafting has resulted in a reproducible, simplified, and organized surgical technique. Recatheterization study has been performed in 39 asymptomatic and 3 symptomatic patients at two weeks to one year postoperatively. Two distal stenoses and no closures have been found. The advantages of internal mammary arteries as bypass grafts are that the vessels are comparably sized, there is artery-to-artery anastomosis, only a single distal anastomosis per graft is needed, there is no subintimal hyperplasia, and no leg wound problems occur. Disadvantages are that a more tedious dissection of the relatively more friable internal mammary vessel is necessary, only two grafts are available whereas multiple bypasses are sometimes necessary, and the grafts are limited in length. Complications specific to the procedure are injury to the internal mammary artery during preparation (2 patients) and inadequate graft size (5 patients). Flow rates are adequate to relieve angina. Patients with subclavian bruits or differential blood pressure between the right and left arms are not considered candidates for internal mammary artery bypass grafting. The availability of a special 7-0 Prolene suture on a BV-1 needle and the use of optical magnification are especially important adjuncts to the procedure.