This contribution deals with the ultrastructure of the pancreatic nervous system of the dog 14 days and 5 months after bilateral truncal vagotomy. No major ultramorphological changes in the axons or their organelles (vesicles, mitochondria, microtubuli) were observed, and there appeared to be no reduction in the numbers of sympathic and cholinergic axis cylinders (material fixed in glutaraldehyde and potassium permanganate) or neurocellular contacts.