We investigated 63 patients with detrusor areflexia by cystometrography, perineal floor electromyography and bethanechol chloride supersensitivity testing. Of the patients 48 had unequivocal evidence of neuropathy, while 15 were neurologically normal and served as controls. The bethanechol chloride supersensitivity test was positive in 98 per cent of the patients and none of the controls, whereas neuropathic changes by electromyography were found in 67 per cent of the patients and 7 per cent of the controls. These findings suggest that the bethanechol chloride supersensitivity test is more sensitive and more specific than perineal floor electromyography in corroborating bladder neuropathy.