Heterotopic gastric mucosa may occur throughout the gastrointestinal tract, including the upper esophagus. The capability of this ectopic mucosa to secrete acid has been suggested in different reports. We report for the first time a case of heterotopic gastric mucosa in the upper esophagus complicated by a stricture with secretion of acid demonstrated by prolonged ambulatory pH monitoring. Lansoprazole, 30 mg twice daily, produced symptom resolution, and repeat ambulatory pH showed complete acid suppression in the proximal esophagus.