Morphological examinations of 115 biopsies of the pancreas showed the peptic ulcer and postgastroresection complications not to be the leading factors in the etiology of the pancreatic pathology. Gastric resection does not favour the affection of the pancreas but may aggravate the existing morphological lesions. Despite the lack of crude histological changes in the pancreatic gland in peptic ulcer, ultrastructural signs of a high functional intensity of acinary cells were found which may also be regarded as pathological manifestations. Most marked changes of the histostructure of the pancreatic gland were found in peptic ulcer of the gastroenteroanastomosis. A difference in the A-cell content of pancreatic insulae before and after gastric resection was found. As the pancreatic tissue is frequently intact in the afferent loop syndrome, the leading role of duodenostasis in chronic affection of the pancreatic gland may be disputed.