Gastric function was studied in 69 peptic ulcer patients in the long-term period after gastric resection according to Billroth-I and Billroth-II. Enzyme-producing function of the stomach was appraised according to the blood pepsinogen content, acid-forming function was assessed with the aid of intragastric pH-metry, and mucus-forming one in accordance with the content of hexosamines and sialic acids in gastric juice. The patients showed different alterations in gastric function. A correlation analysis was used to establish the role played by the neurohormonal systems (leu-enkephalin, beta-endorphin, gastrin, somatotropin, triiodothyronine, thyroxine, cortisol) in the derangement of secretory function of the resected stomach. The data obtained enable one to come closer to understanding the ineffectiveness in some cases of drug and surgical therapy of peptic ulcer. On the other hand, specification of the regularities of the impairment of secretory function of the stomach will be helpful in elaborating methods of gastric function correction at the neurohormonal level.