A prospective controlled trial of proximal gastric vagotomy (PGV) in 829 patients at three surgical services is presented. Peroperative tests of vagotomy completeness were made in two of the three groups of patients. The follow-up period was four to six years. The hospital stay after PGV averaged 9.2 days. The postoperative mortality rate was 0.2%. The reduction of gastric acidity was maintained four years after PGV. Postoperatively no patient had severe diarrhoea. The incidence of dumping after PGV was 1.5% and of gastric stasis 7.3%. Though 7% of the patients reported pyrosis after PGV, only a few required treatment. Transient dysphagia was reported by 2.5% of the patients. In about 4% of the series there were relatively mild ulcer-like symptoms postoperatively, without confirmation of ulcer. Duodenal ulcer recurred in 2% of cases during the observation period and gastric ulcer appeared in 1.5%. According to the Visick classification, 74% of the series showed grade I clinical result, 18% grade II, 4% grade III and 4% grade IV. There were no intergroup differences in Visick grades.