Spinal cord syndromes with a mainly syringomyelic pattern of sensory diorders, radiculopathies, mixed paresis of varying degree (without any history of trauma), have been found in 507 out of 1305 new patients referred to out Clinic from January 1976 till 31 October 1977. In 105 randomised and unselected cases with these syndromes, myelographies have disclosed findings compatible with an adhesive spinal and/or cisternal arachnoiditis. A prospective study of the syndromes for evidence of infectious aetiology has been performed, in which tuberculosis, syphilis and other infections appear to be causative agents. A randomised therapeutic trial on a limited number of cases has been evaluated, as well as the results of specific therapy in a larger number of cases. Results of treatment have not been satisfactory. Operations were performed on only five patients and in no case was an autopsy obtained. Spinal cord syndromes due to non-traumatic adhesive arachnoiditis are discussed. The possible pathogenetic mechanisms the predominantly syringomyelic sensory deficits in those syndromes are briefly mentioned.