Proximal pseudoaneurysm of ascending-abdominal aortic bypass is an uncommon surgical disease. We report a repair of complete detachment of proximal anastomosis of the ascending-abdominal aortic bypass in a 68-year-old man that underwent surgery in 1988 for chronic descending thoracic aortic aneurysm treated with thromboesclusion technique. The clinical, diagnostic, and operative aspects are discussed.