In the Zollinger-Ellison syndrome, fundic argyrophil carcinoid tumors occur almost exclusively in the small subgroup of patients who also have multiple endocrine neoplasia type 1. In these patients, tumor development seems related to the same genetic alterations as those observed in other endocrine tumors related to multiple endocrine neoplasia type 1. We report here the second detailed case of a patient with sporadic Zollinger-Ellison syndrome who developed an argyrophil carcinoid tumor in nonatrophic fundic mucosa, suggesting that chronic hypergastrinemia may lead to fundic carcinoid development in nongenetically predisposed patients.