This report describes a series of 553 flexible upper gastrointestinal (GI) endoscopies performed on 382 children in two surgical centers between 1975 and 1987. Indications included abdominal pain (180), reassessment of known disease (149), upper GI bleeding (99), foreign body ingestion (77), vomiting (14), dysphagia (10), and miscellaneous (24). Findings were chronic peptic ulcer (47), gastritis/duodenitis (63), healing disease (92), nonhealing disease (22), recurrent disease (32), foreign body impaction (22), stricture (9), esophagitis (7), varices (7), mass (6 [3 polyp, 1 lymphoma, 1 fungus ball, 1 inflammation]), normal (209), and miscellaneous (37). Endoscopic diagnosis was uniformly correct except on two occasions, when the presence of recurrent tracheoesophageal fistula in small infants was missed due to use of an inadequate instrument. A pathologic lesion is likely to be identifiable in GI bleeding (84.8%). Endoscopic surveillance for progress of known disease was found to be valuable, particularly in peptic ulcer management, as both incomplete healing after standard therapy as well as recurrence are frequent. The recent practice of routine antral biopsy in children with severe "nonspecific abdominable pain" enabled four cases of Campylobacter pylori colonization in the stomach to be diagnosed, thus allowing appropriate treatment. Endoscopy was therapeutic on 61 occasions: injection sclerotherapy (32), foreign body removal (20), polypectomy (3), and stricture dilatation (6). Endoscopy-guided bougienage, in particular, represents a recent major advance. There was no morbidity or mortality in the entire series. It is concluded that pediatric upper GI endoscopy performed by experienced surgeons is safe and effective. As a result of better understanding and technological advances, a changing trend of wider and more rational applications of the procedure is now evident.