A patient with long-standing Crohn's disease of the large and small intestine was found to have extensive gastric metaplasia of the ileum. Most metaplastic glands were of the pyloric type, but numerous oxyntic glands with parietal and chief cells were also seen. By immunofluorescence the chief cells contained both the group I and group II pepsinogens, while the pyloric gland cells contained only the group II pepsinogens. Gastric-containing or other endocrine cells were not detected in the metaplastic pyloric and oxyntic glands. The latter findings are consistent with the concept expressed by Pearse that the endocrine and exocrine cells of the gastrointestinal mucosa may originate from different precursor elements during embryogenesis.