Saphenous vein graft pseudoaneurysms are an unusual but potentially fatal complication of coronary artery bypass grafting because of their high risk of rupture or thromboembolism. We experienced the case of a 58-year-old man with a saphenous vein graft pseudoaneurysm with a floating thrombus that had developed 17 years after the initial coronary artery bypass grafting. The prevention of thromboembolism during a surgical procedure has been crucial for this type of operation. We developed the idea of in situ revascularization using the right gastroepiploic artery under the beating heart on cardiopulmonary bypass followed by an aneurysmectomy under an arrested heart.