We have found 20 cases of ectopic gastric mucosa in the proximal esophagus. Five patients had symptoms, usually a burning sensation in the neck and/or dysphagia. We report the results of immunoperoxidase staining of this tissue for gastrin, somatostatin, vasoactive intestinal peptide, and bombesin. In 85% of biopsy specimens tested, one or more polypeptides were present. Gastrin and bombesin were found more frequently in symptomatic patients, and somatostatin in asymptomatic patients. Chronic inflammatory changes were more frequent in symptomatic patients.