Pain in the lower extremities associated with occlusive arterial disease is a common occurrence. On relatively rare occasions, pain in the legs, precipitated by walking, is caused by compression of the cauda equina by hypertrophic ridging or by a herniated lumbar disk. The symptoms of six patients resulted from such compression of the cauda equina. There are clinical characteristics which may help in distinguishing the symptoms of occlusive arterial disease from those of degenerative disease of the lumbar part of the spinal column. The pathophysiologic mechanisms involved in the production of symptoms in the syndrome of "pseudoclaudication" remain obscure.