In three centres, 222 patients (Birmingham 70, London 87 and Rotterdam 65 patients) with chronic duodenal ulcer were treated by proximal gastrict vagotomy (PGV) (116 patients) or truncal vagotomy and antrectomy (TVA) (106 patients) in a prospective randomized trial. After 1 year 5 recurrent duodenal ulcers (4.3 per cent) have been recorded in the PGV group, compared with 1 (1 per cent) in the TVA group. The reoperation rate was high in both groups-6 after PGV, usually for recurrent ulcer, and 7 after TVA, mostly for gastric retention. PGV showed a marked superiority in the number of patients with a good clinical result Visick I or II) at 1 year after operation, i.e. 82 per cent compared with 56 per cent for TVA.