In 152 consecutively selected patients with detrusor hyperreflexia (DH) 96 (63 per cent) had neurological disorders. Thirty-two patients did not show any primary neurological or urological cause for DH. This group was chosen to elucidate the evaluation of possible neurological symptoms in relation to the urological symptomatology. Nine had died and one failed to appear to the neurological examination. Twelve (63 per cent) of the 22 examined patients showed signs of lesions in different parts of the central nervous system, particularly cerebrovascular diseases and myeloneuropathy. Six had had neurological symptoms for years. In two the urological symptoms were first to appear. In the group with no neurological complaints the urological symptoms had existed for 2-30 years. No essential difference was found in the degree of voiding disturbance whether or not neurological signs were disclosed. It is concluded that the discovery of DH should be followed by a neurological examination to disclose further signs of lesions in CNS. Likewise, an extended urological examination with demonstration of DH might help in the evaluation of an obscure neurological disease.