Forty-seven patients with an abdominal aortic aneurysm (AAA) and recent onset of abdominal or back pain were evaluated by emergency computed tomography (CT) to identify those patients with a confined rupture, and unstable aneurysm, nonaneurysmal cause of pain and a stable AAA. CT suggested that 25 per cent of these had a confined rupture and should undergo emergency surgical treatment. Rupture was confirmed at operation in one-half of these instances. Thirteen per cent avoided operation since other significant pathologic factors were identified. The remaining 47 per cent benefited from optimal preoperative evaluation and semielective surgical treatment. No patient ruptured an AAA during the delay for complete preoperative evaluation and preparation. Additionally, a preoperative CT is useful to identify patients with an unsuspected iliac, suprarenal, thoracic or inflammatory aneurysm. Thus, we believe that CT has a particularly important role in the evaluation of the symptomatic AAA, adding it to the list of indications for CT evaluation of difficult aortic disorders.