Between 1966 and 1976, 65 infants and children were treated because of hiatus hernia. The diagnosis was made radiologically in all cases and in a number of patients endoscopically. 54 patients had a forme mineure (types 1 and 2), and 11 had a forme majeure (types 3 and 4). Of the 20 patients with type 1, 16 (80%) were successfully treated conservatively; two further patients needed a secondary operation. Of 34 children with type 2, 15 (44%) were treated successfully conservatively, and four needed a secondary operation. Of ten patients with type 3, four (40%) were treated primarily conservatively with success. Two children with type 1, 11 with type 2, six with type 3, and one with type 4 had to be operated on primarily because of severe esophagitis at the time of admission. From 14 mon to 10 years after discharge from hospital, follow-up examination of 33 patients showed that one child died from another cause. In 14 of the 21 conservatively treated patients and in 12 of the 18 surgically treated patients (66% in both cases), there were no symptoms or complaints. Eight had subjective complaints, but in only four (10.5%) was there a definite complaint. Three of these four patients had associated diseases (spastic tetraplegia, operated jejunal atresia). In these patients, esophagitis was present on follow-up examination and necessitated further treatment. The treatment of choice for the forme mineure without esophagitis should be conservative, and in most cases this will be sufficient. In only a few of these patients did it become necessary to carry out a secondary fundoplication. Operation is indicated primarily in cases with esophagitis and esophageal stenosis as well as in patients with a forme majeure of the hiatus hernia.