Four cases of retrograde prolapse of the gastric mucosa into the esophagus are reported, and the literature briefly reviewed. Whether this entity represents a clinical and roentgenographic disorder or fits into the spectrum of hiatus hernia is debatable. The clinical symptoms are those of hiatus hernia and gastroesophageal reflux. Of importance is the fact that the roentgenographic findings may simulate an esophageal neoplasm. The diagnosis may be suggested by the roentgenographic findings of one or more changeable distal esophageal filling defects and confirmed by esophagoscopy.