The autonomic innervation of the human vas deferens was studied histochemically. In the well-developed smooth muscle layers there were a small number of delicate adrenergic nerve terminals. Varicose nerve terminals able to take up and bind quinacrine were also found. These nerves may represent a specific nerve population previously denoted as "purinergic" nerves. In contrast, nerves displaying acetylcholine esterase (AchE) activity and/or immunoreactivity specific for vasoactive intestinal polypeptide (VIP) were mainly found subepithelially in the connective tissue of the mucosa.