A total of 30 patients with an established diagnosis of Parkinson's disease and symptomatic voiding dysfunction underwent neurourologic evaluation. Detrusor hyperreflexia associated with appropriate sphincter relaxation was found to be the most common urodynamic pattern, occurring in 75 per cent of the cases. Two types of increased electromyogram activity at the time of detrusor contraction were identified: 1) pseudo-dyssynergia (7 per cent)--a voluntary contraction of the perineal floor in an attempt to prevent leakage and 2) sphincter bradykinesia (11 per cent)--a manifestation of skeletal muscle hypertonicity characteristic of parkinsonism. On the basis of these observations it is assumed that the effect of the basal ganglia on micturition is inhibitory in nature. The diagnostic and therapeutic approach to the parkinsonian patient with voiding dysfunction is discussed.