Elective resection and prosthetic graft replacement of asymptomatic abdominal aortic aneurysms 5 cm or more in diameter are dependable measures to counter the formidable threat of rupture. Operative mortality should be less than 5% among patients without severe associated disease. Those patients who have large aneurysms but who represent marginal risks for major vascular repair may be guided through such an operation with reasonable safety by meticulous preoperative and postoperative care. Particular attention should be devoted to assessment and support of pulmonary and renal function and to detection of associated arteriosclerosis of the coronary and carotid arteries.