The hypothesis is advanced that the functional urethral obstruction found in neuropathic states is due, in part at least, to urethral supersensitivity following sympathetic decentralisation. A simple postural test for this condition is described. By its use it has been shown that urethral denervation occurs not only in disorders of the central nervous system but with peripheral damage such as may result from rectal excision and hysterectomy. In some cases with functional urethral obstruction, attributable to suersensitivity of the urethra, no neurological abnormality has been found. These may be examples of localised visceral neuropathy.