A 57-year-old black man presented with a pulsatile gluteal mass and claudication. Angiography revealed a persistent sciatic artery to be the main arterial supply to the limb; this vessel had a false aneurysm caused by atherosclerotic rupture of its gluteal portion. It was successfully treated by excision and an autologous vein graft. A brief survey of this rare condition -- the embryology, and the angiographic and clinical features -- is given. The importance of recognising the symptoms is emphasised.