Vascular complications in von Recklinghausen disease are rare, especially spontaneous rupture of a major artery. A 50-year-old man with previously diagnosed neurofibromatosis was admitted because of spontaneous rt-sided lumbago, paresthesia in rt-lower limb and severe anemia. Angiographic studies, CT and MRI revealed pseudo-aneurysm of bilateral lumbar arteries, which ruptured into the psoas muscle. Both arteries were ligated and hematoma was removed. The pathogenesis of the spontaneous rupture is discussed.