The regional distribution of peptidergic nerves in the juvenile and adult human prostate has been studied immunohistochemically using highly specific polyclonal antibodies. Nerves displaying immunoreactivity of Met-enkephalin, Leu-enkephalin, heptapetide and octapeptide were detected in the dorsolateral stroma closely related to smooth muscle predominantly of juvenile glands. A less strong immunoreactivity was present around stromal vessels and periurethral. Subepithelial periacinar nerves showing Leu-enkephalin, Met-enkephalin, octa- and heptapetide immunoreactivity were found in a few instances. The most prominent immunoreaction was achieved with octapeptide antiserum, followed in decreasing order by Met-enkephalin, Leu-enkephalin and heptapeptide. Their density decreased with age. Antisera against Β-endorphin, Α-neoendorphin, Β-neoendorphin and dynorphin A gave to positive immunoreaction with prostatic nerves. The regional distribution pattern described is in favor of a postsynaptic peptidergic sympathetic innervation of prostatic stroma acting with classical neurotransmitters.