Diagnostic features of glycogenic acanthosis of the esophagus on air-contrast radiography, endoscopy, and histopathologic studies in 10 selected cases are presented. Glycogenic acanthosis of the esophagus is a common benign entity, characterized by multifocal plaques of hyperplastic squamous epithelium with abundant intracellular glycogen deposits. At esophagoscopy or on autopsy specimens these lesions appear as slightly raised grey-white plaques which are usually 2-10 mm in diameter and may be confluent. They cause a finely nodular or cobblestone mucosal pattern demonstrable on double-contrast views of the well-distended esophagus. The findings are not associated with mucosal ulcerations, luminal narrowing, or mobility disturbance, although some patients may have coexistent hiatal hernia and gastroesophageal reflux.