The article analyses the results of pylorus-preserving resections of the stomach in 116 patients among whom 80 had gastric ulcer, 29 ad duodenal ulcer, and 7 had gastroduodenal ulcers. Changes of acidity and motor-evacuation function of the gastric stump were studied according to the method of pylorus-preserving resection. The late-term results of treatment in follow-up periods of 2 to 5 years are shown, they were found to be good in 96.6% of patients treated by operation and poor in 1.7%. It is noted that the function of the gastric stump is better when the vagus innervation of the pylorus is preserved. Mediogastric resection with selective proximal vagotomy in patients suffering from duodenal ulcer with a superacidic stomach led to stable normalization of acid production, which was a reliable measure for the prevention of a recurrent ulcer.