In a retrospective study of 320 gastroduodenoscopies performed on children in the last 2 years, 32 cases of duodenal damage, either isolated or associated with esophagitis, gastritis, or both, were selected. Twenty matched children with dyspeptic symptoms but an endoscopically normal duodenum were chosen as controls. Histological sections of fiberoptic biopsy specimens were submitted to double-blind examination by two observers: only four fulfilled accepted criteria for histological duodenitis. The concordance between endoscopic and histological results in our patients was 13.8%. No changes of duodenal endoscopic appearance predictive of duodenitis were identified. In 8 more cases (6 patients and 2 controls) the histological examination showed an isolated lymphocyte and plasma cell infiltration of the lamina propria without any additional damage. We called this picture "minimal change duodenitis" and considered it as a variation of normal. In 17 patients and 11 controls, basal and maximal acid outputs were calculated and no significant differences were found. We concluded that duodenitis in children may be present, although rare, and its diagnosis requires histological examination of duodenal mucosa.