Of 55 children (age 3 months to 16 years) who had fundoplication, major complications occurred in nine (16 per cent): paraoesophageal hernia (five cases), prolonged ileus (two cases), recurrent gastro-oesophageal reflux (one case), and accidental perforation (one case). The single most important factor resulting in complications was the omission of crural repair; of seven patients without crural repair, five developed paraoesophageal hernia/recurrence. Four patients required repeat fundoplication for severe recurrent symptoms and one of these developed the unusual complication of pericardiogastric fistula. Thirteen patients had strictures before operation from reflux oesophagitis, six (46 per cent) resolved after fundoplication alone, six responded to dilatation (mean five sessions), and one required colon interposition. Our preliminary experience with balloon dilatation was encouraging: three of three patients responded after one dilatation only. These results confirmed the efficacy of surgery in controlling reflux: 100 per cent in the short-term and 89 per cent on a 1-6 year follow-up. Major complications might well be reduced by routine crural repair.