In eleven patients with acute disseminated encephalomyelitis (ADEM), micturitional histories taken during the acute stage revealed that nine were in a state of urinary retention, and the other two had urinary frequency and urge incontinence together with difficulty in voiding. After the follow-up period of 3 to 38 months seven of nine patients with retention became able to urinate, but five of them had difficulty in voiding and four of them developed urinary frequency or urge incontinence. Two patients had urinary retention even after 26 and 38 months from the onset, Ten patients underwent urodynamic studies and disclosed detrusor hyperreflexia in six, low compliance bladder in two, atonic cystometrogram in one and detrusor-sphincter dyssynergia in two patients. Motor unit analysis of the external sphincter revealed polyphasic neurogenic changes in one of four patients, The results were compared with our previous findings in multiple sclerosis (MS), and we found that micturitional disturbance in ADEM seemed to be as common and as severe as in MS. Supranuclear as well as nuclear types of pelvic and pudendal nerve dysfunction seemed to be responsible for micturitional disturbance in our patients with ADEM. Micturitional disturbance seemed to be related to the pyramidal tract involvement, and probably reflecting the severity of spinal cord lesions.