The chief cell mass and serum pepsinogen I (PGI) have been evaluated in 18 patients with gastric cancer of intestinal type of the body-fundus. Moreover, a correlation with the parietal cell mass and the maximal acid output it has been effected. The patients have been subdivided in relation to histologic condition of the fundic mucosa. In case of gastric cancer with preatrophic fundic gastritis it has been revealed hypozymogenism with normoPGI and hypoparietalism with hypochlorhydria, in case of gastric cancer with atrophic fundic gastritis it has been revealed hypozymogenism with hypoPGI and hypoparietalism with hypochlorhydria. From this experience it emerges a similar anatomic-functional profile between gastric cancer of the body-fundus and chronic fundic gastritis without cancer. In particular, it emerges that serum PGI is a good marker of atrophic fundic gastritis, but it is not discriminant between atrophic fundic gastritis and atrophic fundic gastritis associated to gastric cancer.