An histochemical research on cholinergic and noradrenergic fibres of the adventitia layer and of the myenteric plexus of the terminal ileum from rats with streptozotocin-induced diabetes, after 20 weeks of evolution of the illness, was carried out to study changes in the innervation of the gut. The cholinergic nerves, revealed through their acetylcholinesterase activity, did not present alterations, but an evident reduction in number of the noradrenergic nerves and swollen intensely fluorescent varicosities, were observed, both in the perivascular and myenteric plexus of terminal ileum from diabetic animals.