The arrangement and distribution of intramural autonomic ganglion cells have been examined in samples of the dome and lateral walls of the human urinary bladder. Ganglia were frequently observed in samples removed from either site and possessed histochemical characteristics to support their classification as presumptive cholinergic neurons. Unlike pelvic autonomic neurons, intramural bladder ganglion cells are not associated with noradrenergic (possibly inhibitory) preganglionic nerve terminals. The widespread distribution of ganglion cells within the bladder wall serves to frustrate surgical attempts to denervate detrusor smooth muscle. The outcome of such operative procedures is likely to result in decentralisation rather than denervation of the urinary bladder.