Hypoplasia of the distal abdominal aorta, first described by Quain in 1847, is rarely associated with atherosclerotic occlusive disease. The condition usually occurs early in life; the principal clinical features are hypertension and arterial insufficiency of the lower extremities which is often well tolerated. Some 20 patients had operations for abdominal aortic hypoplasia; 16 underwent prosthetic reconstruction and four had aortoiliac endarterectomy with angioplasty. Reconstructive techniques were influenced by narrow renal arteries and by the presence of extensive atheroma. The long-term prognosis is often poor, especially in patients with extensive disease.