AbstractTwenty patients with duodenal ulcer have been treated by a pylorus‐preserving gastrectomy. A functioning pyloric sphincter was maintained by retaining a 2‐cm. cuff of antrum and carrying out a Billroth‐I type of resection proximally. Basal acid output was reduced by 52.4 per cent and maximal acid output by 65 per cent. Gastric emptying time was prolonged, without producing stasis. A provocative test for the presence of dumping produced symptoms in only 1 patient following this operation in comparison with a high incidence of symptoms in patients who had had a Polya gastrectomy or vagotomy and drainage.The results suggest that the procedure may be of value in the treatment of chronic duodenal