The gastric mucosa in 113 children from 6 months to 14 years old was studied from a histopathological point of view. Samples were obtained by means of a multiple biopsy technique during an endoscopic examination. The patients were divided into two groups. Group A was composed of 97 children with abdominal pain of an unknown etiology. Group B was formed of 16 patients with extragastric pathology in whom it was possible to take biopsies during an endoscopic exam. All of the biopsies were normal, and therefore were used as the control group. 49 patients from group A were histologically normal. In the other 48, lesions of chronic gastritis ranging in severity, were found in the antrum and/or in the gastric body. An analysis of the histopathological findings, and of the lesional sings of activity was done in accordance with Whitehead's criteria. Macroscopic objective features observed during the endoscopical examinations, were also evaluated and compared with the existence or nonexistence of chronic gastritis lesions. In the gastric body, the existence of endoscopic features such as enlarged folds, erosions or friable mucosa, were found to be coincident with the presence of histologic lesions of chronic gastritis. The same relationship was found in the antrum between the granular mucosa and/or irregular coloration and the lesions of chronic gastritis. In the same time, acid secretion studies (BAO, MAO and PAO) from 40 patients from group A were done using pentagastrin as a stimulant. It was demonstrated that both basal acid output and maximal acid were significantly lowered in cases of advanced lesions of chronic gastritis located in the gastric body. Finally the importance of this entity is emphasized in the gastrointestinal pathology in children.