Nine patients with persistent hyperinsulinaemic hypoglycaemia of infancy (PHHI), aged 3 days to 11 months, received octreotide therapy at a dose of 5-10 micrograms s.c. every 4-8 h according to glucose response. The response to octreotide was variable and unpredictable. Two patients could not be weaned off intravenous glucose and 2 others could be weaned off but required continuous nasogastric feedings. In the remaining 5 patients relatively normal feeding schedules were instituted. Long-term ambulatory treatment is an attractive alternative to surgery in such patients if the family can cope with the injections and dietary regimens. Although octreotide suppresses growth hormone secretion, all patients continue to grow during octreotide treatment.