Histologic sections of 205 gastrectomy specimens, which were obtained for benign and malignant diseases, were reviewed. All patients were Mexican nationals. The following histologic features were recorded: intestinal metaplasia, intramucosal cysts, ciliated gastric cells, and different types of pyloric cells ("ordinary"; with granular cytoplasm; with small cytoplasmic vacuoles; with large cytoplasmic vacuoles; or with homogeneous "glassy" cytoplasm). The percentage of specimens showing intestinal metaplasia was similar in those containing gastric ulcers (42.7%) or adenocarcinomas (50.0%). Intestinal metaplasia was decreased in men 59 years of age or older and in women 69 years of age or older. Diffuse-type adenocarcinoma accounted for 90% of the gastric tumors. Only 3 of the 205 specimens (1.9%) contained intramucosal cysts, and only 1 (0.4%) showed ciliated cells. Pyloric cells with granular cytoplasm were observed in 21.2% of the specimens, and pyloric cells with small cytoplasmic vacuoles were seen in 1.9%. Pyloric cells with large vacuoles or "glassy" cytoplasm were not found in any case. These results indicate differences in the proportions of several histopathologic findings in the gastric mucosa, between Mexicans and other ethnic groups that have been investigated in previous surveys. The authors' findings support the hypothesis that different environmental factors, acting in disparate geographic regions, may account for dissimilarities in the histologic appearance of "normal gastric mucosa."