In a group of 300 patients with the diagnosis of lumbar nucleus pulposus prolapse treated surgically the authors found in 4 cases not the expected prolapse but varicose blood vessels surrounding the nerve roots and immobilizing them in adhesions. In another 5 patients vertebral canal varicosities were associated with nucleus pulposus prolapse. None of these cases of vertebral canal varicosities had been diagnosed before operation since the clinical state of these patients was not significantly different from the state of patients with nucleus prolapse and radiculography failed to supply sufficient diagnostic data or suggested presence of small prolapse. An auxiliary diagnostic finding in cases of vertebral canal varices may be frequent association of spinal anomalies (in 3/4 of the observed cases) and obesity (in 2/3 of cases). Surgical decompression of vertebral canal and liberation of roots from adhesions without excision or ligation of varicose veins gave good therapeutic results.