Following a period of two years with gradually increasing dyspnoe, the patient, a 29-year-old man, suddenly developed acute respiratory distress. On admission to hospital, blood pressure was 260/110, and there were no femoral pulses. Cine-angiography of the aorta revealed a total occlusion from the level of the first lumbar vertebra to the renal arteries. An extensive collateral circulation was visualized. Kidney function was normal. At operation, the aorta was as hard as stone, but the calibre was normal from the diaphragm down to the renal arteries. A dacron graft was inserted, end-to-side between the thoracic aorta and the abdominal aorta distal to the inferior mesenteric artery. Postoperatively, the systemic and ankle blood pressure became near normal. The aetiology of the aortic changes remains unknown. Several possibilities are considered, among them abdominal aortitis and cystic necrosis of the media. Coarctation of the abdominal aorta is less likely, as no narrowing of the aorta was seen at operation.