True aneurysms of aortocoronary saphenous vein bypass grafts are a relatively rare complication of bypass surgery, but because the complications of thrombosis, embolization, or rupture are potentially fatal, this condition requires immediate surgical intervention. We describe a 78-year-old man who had undergone coronary bypass 15 years previously and who presented with a saphenous vein graft that was severely degenerated and aneurysmally enlarged throughout its course, measuring as much as 5 to 6 cm in certain locations. Redo coronary artery bypass grafting using the right and left internal thoracic arteries and resection of the aneurysm were performed. We also present a review of the literature regarding diagnosis, management, and treatment of this condition.