Between February 1972 and December 1976 100 proximal gastric vagotomies (PGV) were performed on duodenal ulcer patients after failure of conservative treatment. The diagnosis was verified by preoperative barium meal and endoscopy and by peroperative examination. There was no operative mortality. Mean duration of postoperative hospital stay was 9.6 days. The percentual distribution in Visick-grading at the 1-year follow-up was 90% in class I + II, and 10% in class III + IV. The corresponding figures at the 5-year follow-up were 82% and 18%. The mean postoperative basal acid output did not change from one to five years. The reduction in pentagastrin stimulated acid output was unchanged at the 1- and 5-year follow-up. Neither did the mean acid output after insulin stimulation change between one and five years postoperatively. The mean concentration of serum gastrin was raised at one year but decreased to normal at the 5-year follow-up. Ten patients (10%) had ulcer recurrence during follow-up. Seven of these were successfully treated by gastric resection and three by antacids and cimetidine.