It is widely acknowledged that Barrett's esophagus in adults is an acquired condition resulting from prolonged gastroesophageal reflux. Barrett's esophagus is rare in childhood, even though gastroesophageal reflux occurs commonly in the pediatric age group. When a columnar-lined esophagus is present in children, it is often regarded as a congenital anomaly rather than as a consequence of chronic gastroesophageal reflux. Over a 5-yr period (1978-1982), we retrospectively studied Barrett's esophagus in children 19 yr of age or younger who were evaluated for gastroesophageal reflux and whose symptoms warranted esophagoscopy and esophageal biopsy. Esophageal biopsies were performed on 103 patients with gastroesophageal reflux. Thirteen children (age range, 8 mo-19 yr) had Barrett's esophagus, for a prevalence of 13%. Gastroesophageal reflux was documented in these children by upper gastrointestinal radiographs or pH monitoring. Radiographs demonstrated esophageal stricture in 5 of the 13 children; none had hiatal hernia. Children presented with symptoms suggestive of gastroesophageal reflux and esophagitis: vomiting, abdominal pain, odynophagia, dysphagia, and heartburn. All children had a past history of excessive regurgitation during infancy. Histologically, three types of columnar epithelium were present: gastric fundic type (11 patients), junctional-type columnar epithelium reminiscent of gastric cardia (7 patients), and specialized columnar (metaplastic intestinal) type (2 patients). We believe that Barrett's esophagus is more common in children than had previously been appreciated. In these children, we suggest that the distal columnar-lined esophagus resulted from chronic gastroesophageal reflux and is not a congenital anomaly.