Epstein-Barr virus (EBV) has been implicated in the genesis of gastric carcinoma. The presence of clonal episomal viral forms in the nuclei of neoplastic gastric epithelial cells suggests that viral infection occurs before the development of gastric carcinoma. Mexico is a country at high risk for gastric cancer-it is the second cause of death among patients who die of cancer in that country. A series of 135 consecutive non-selected gastrectomies from two hospitals in Mexico City were analyzed to search for EBV in gastric carcinomas. EBV-encoded small non-polyadenylated RNA (EBER) in situ hybridization was performed on 5-microm paraffin-embedded tissue sections. Age, gender, anatomical site, histological type, and invasiveness of gastric carcinomas were obtained from the records in the corresponding Departments of Pathology. Eleven (8.15%) of the 135 cases were EBER-1-positive gastric carcinomas. Six occurred in males and five in females. In three women, the neoplasia was localized in the antrum. Five of the 11 cases were lymphoepithelioma-like carcinomas and, in two of them, an unusual foreign body-type inflammation was observed. Environmental factors could influence the distinctive pathologic features of EBV-associated gastric carcinoma in the Mexican population.