The clinical and angiographic findings of 55 patients with a spinal dural arteriovenous malformation (AVM) are reviewed, and the results of surgery assessed. The symptoms of dural AVM are usually gradual in onset, and hemorrhage from this type of AVM is less common than in true spinal cord angiomas. Other clinical features and the myelographic findings are similar to those of spinal cord angiomas. On angiography, the nidus of dural AVM's usually projected lateral to the spinal cord. Clipping of communicating vessels between the AVM and the coronal plexus was carried out in 50 patients, and decompressive laminectomy only in five cases. Surgery led to improvement of disturbed gait or arrest of a previously progressive course in 85% of those managed by clipping communicating vessels. The pathophysiology and surgical treatment of dural AVM's are discussed.