Biopsy samples of gastric mucosa were obtained at endoscopy from patients suspected of having intestinal metaplasia. These samples were prepared for light microscopy and scanning electron microscopy. Observations of the luminal surface of the gastric mucosa in the scanning electron microscope revealed distinct topographic differences in the intestinalized and nonintestinalized regions. The latter area showed features consistent with those described in chronic gastritis, i.e., the exaggeration of the "cobblestone relief" appearance of the luminal surface of the stomach and the presence of numerous short, stubby, bulbous microvilli which project from the free border of the surface mucous cells toward the lumen of the stomach. The intestinalized region revealed a plush microvillous (striated) border periodically interrupted by apical openings of goblet cells. The scanning electron microscope is a useful research aid for examination of cell membrane expressions of the surface cells of the gastric mucosa not totally appreciated by light microscopy and transmission electron microscopy.