Clinical effects of oxybutynin hydrochloride on lower urinary tract function at a dosage of 2 mg given orally three times daily (6 mg/day), were studied on 10 patients with neurogenic bladder by cystometry and measurement of residual urine. There was a significant increase, of about 34% in FDV, but no significant changes in MBV, or maximum voiding pressure of residual urine after administration. Urinary frequency, incontinence and urgency in subjective symptoms were decreased in patients given this drug. The effective rate (excellent and good) was 50% in global evaluation. Side effects were observed in 4 out of 10 patients; 3 had dry mouth and 1 had diarrhea. There were no serious side effects. These findings suggested that oxybutynin hydrochloride may be a useful drug for neurogenic bladder.