Ten patients with neurogenic detrusor hyperreflexia were treated by percutaneous radiofrequency sacral rhizotomy. All had low-threshold involuntary micturition. The bladder capacity of seven patients was increased to over 290 cc during a follow-up interval of 3 to 18 months. This convenient percutaneous procedure is particularly suited for controlling detrusor hyperreflexia, which has frequent failures of initial treatment and late recurrence of symptoms.