The present study of 71 patients shows that the initial symptoms often cannot differentiate spinal cord arteriovenous malformation from other lesions causing cord dysfunction, but the picture at the time of presentation may suggest the diagnosis. Most patients are males with neurologic findings referable to the thoracolumbar area who present with gradually progressive pain, weadness, sensory distubance, and disturbance of micturition. Early impairment of micturition may help suggest this lesion because it is less likely to be an early complaint in patients with disk disease or tumor affecting the spinal cord. Symptoms occasionally vary with posture and exercise and menses. Most commonly there are combined upper motor neuron and lower motor neuron manifestations with nonradicular sensory deficit. The cerebrospinal fluid is abnormal in more than 75% of cases. The myelogram is positivie in 75 to 90% of cases and the angiogram is almost always diagnostic.