A retrospective analysis of data on all infants with persistent neonatal hyperinsulinism (PNH) in our hospital during a nine-year period (July 1983 to June 1992) was carried out. The extent of pancreatectomy and outcome based on long-term follow-up were reviewed. Fourteen of the 18 cases, diagnosed at our facility according to the established criteria of PNH, underwent surgery. Two patients who were managed medically because of milder disease and reluctance of parents for surgery and two patients who were diagnosed and operated upon outside our facility were excluded from this study. One patient, operated upon in 1985, needed re-surgery after 95% pancreatectomy because of recurrent hypoglycaemia unresponsive to medical treatment. This case influenced our management in a subsequent patient in whom we performed total pancreatectomy as an initial procedure. Both these patients are still diabetic. Three more patients had recurrence of hypoglycaemia after 95% pancreatectomy, two were managed successfully with a short course of diazoxide, the third had associated carnitine deficiency and his hypoglycaemia resolved after a short period of carnitine therapy. The first patient in our series had 85% pancreatectomy, the other 11 patients had 95% pancreatectomy as an initial procedure. The 12 patients are normoglycaemic and off all medication. We conclude that 95% pancreatectomy as an initial procedure for PNH offers the best prognosis and that recurrence of hypoglycaemia does occur following 95% pancreatectomy and can easily be managed medically.