A case of acute renal infarction due to Behçet's disease is described. Selective renal arteriography revealed multiple microaneurysms of both kidneys and arterial obstruction distal to an aneurysm in the left kidney. Bilateral microaneurysms were no longer seen on the follow-up angiogram 5 years later. Behçet's disease should be considered in the differential diagnosis of acute renal infarction in young adults.