In a prospective study we analyzed the recurrence rates in 505 patients with a chronic duodenal, intrapyloric or prepyloric ulcer. In the period from 1973 to 1982 the 5-year recurrence rate in 392 patients after proximal gastric vagatomy was 10% for the intrapyloric and 14.5 % for the duodenal ulcer, whereas patients with a prepyloric ulcer had a recurrence rate of 29%. Since 1982 our therapy of choice for the prepyloric ulcer has therefore been antrectomy and selective gastric vagotomy. The recurrence rate in 19 patients with a prepyloric ulcer treated by this procedure was now 0%. Furthermore we analyzed and discussed acid and gastrin secretion in this group of patients in relation to the different ulcer localizations.