In a series of 584 patients undergoing coronary bypass, 425 patients received Y-grafts, sequential grafts, or a combination of the two. The saphenous veins from the legs frequently had Y- or double Y-branches suitable for bypasses. As many as 5 grafts have been served satisfactorily by a single proximal anastomosis. Simultaneous procedures included 45 left ventricular aneurysmectomies, 18 valve replacements, 7 carotid endarterectomies, repairs of a ventricular septal defect, an acute dissection, and coronary arteriovenous fistulas, with a total surgical mortality of 6 (1.4%). Restudy to determine graft patency was undertaken only in the 59 patients with unsatisfactory surgical results. These patients represent the worst 10% of the series in terms of surgical results. The patency rate for proximal anastomoses was 93%; Y-branchings, 93%; distal end-to-side anastomoses, 89%; and distal side-to-side anastomoses, 89%. Fifty-eight patients (98%) had at least 1 patient graft, and in 47 patients (80%) all anastomoses were patent up to six years after operation. Six patients underwent reoperation without any deaths.