Detailed micturitional histories were taken from nine patients with progressive supranuclear palsy (PSP), and eight of them (89%) had micturitional symptoms including urinary incontinence in seven. Urodynamic studies were performed in six patients and the results were as follows. Three had residual urine of 100 ml on average. Four had detrusor hyperreflexia and one had a low compliance cystometrogram. One had detrusor-sphincter dyssynergia. Motor unit analysis of external sphincter was performed in four patients and two had neurogenic changes. The results were compared with our previous findings in Parkinson's disease and in striato-nigral degeneration (SND), and we found that a severe degree of micturitional disturbance in PSP seems to be as common as in SND, especially in the urinary storage phase, and more frequent than in Parkinson's disease. Supranuclear types of pelvic and pudendal nerve dysfunctions seemed to be mainly responsible for micturitional disturbance in PSP.