Highly selective vagotomy for duodenal ulcer was performed on 307 patients between 1973 and 1983 without operative mortality. Of these, 283 (92.2 per cent) were followed up prospectively for a minimum of 5 years. Recurrent ulcer was diagnosed in 49 (17.3 per cent). The recurrent ulcer rate increased from 13.2 per cent at 5 years to 19.4 per cent at 12 years. Age, length of history, previous haemorrhage or perforation and preoperative acid output were not associated with increased risk of recurrent ulceration. The risk in men and smokers was higher but not significantly so. The recurrence rate for individual surgeons varied from 5.3 to 25.6 per cent. Failure of healing with H2-receptor antagonists was not associated with a higher recurrent ulcer rate. Patients with a strong family history (more than one first degree relative affected) had a significantly higher recurrence rate (33.2 per cent at 10 years) than those without (13.5 per cent at 10 years). Of the 49 recurrent ulcer patients, 30 (61.2 per cent) required either an operation or regular H2-receptor antagonists. Of the 250 patients (81.4 per cent) available in 1988 for review of symptoms 5-15 years after operation, 5.4 per cent had dumping, 8.9 per cent epigastric pain, and 11.8 per cent heartburn every day or most days. H2-receptor antagonists were required by 10.7 per cent of patients on a frequent or regular basis. Of 239 patients who answered the question, 218 (91.2 per cent) felt that their symptoms had been cured or greatly improved and 203 (84.9) considered the operation a success. Despite the high recurrence rate, the operation was successful in controlling ulcer symptoms in around 90 per cent of patients and produced postvagotomy symptoms--none severe--in around 5 per cent of patients.