The long term clinical results after proximal gastric vagotomy (PGV) for peptic ulcer were determined among 396 patients who underwent surgical treatment at the Mayo Medical Center between 1973 and 1981. PGV was performed for duodenal ulcer (n = 293), midgastric ulcer (n = 14), prepyloric or pyloric ulcer (n = 46) and combined gastric, pyloric, prepyloric and duodenal ulcers (n = 43). Postoperative follow-up observation ranged from five to 13 years (a mean of eight years) and was complete in 96 per cent of the patients. There was no perioperative mortality. Severe dumping and diarrhea were uncommon (less than 1 per cent), and only eight patients (2 per cent) had reoperations for nonulcerative complications. Documented recurrent ulcer appeared in 55 patients (14 per cent). Kaplan-Meier estimates of the probabilities of recurrence at five and ten years after PGV, respectively, were duodenal ulcer, 6 and 12 per cent; gastric ulcer, 16 and 16 per cent; pyloric or prepyloric ulcer, 12 and 39 per cent, and combined ulcers, 26 and 33 per cent. Reoperation for recurrence was required in only 16 of the 55 patients (29 per cent). We conclude that PGV for peptic ulcer is a safe operation with few serious side effects. When used to treat duodenal and perhaps midgastric ulcers, PGV has an acceptable long term recurrence rate. The high incidence of recurrent ulcer after PGV for pyloric or prepyloric or combined ulcers suggests that alternative operations should be performed for ulcers in these locations.