Helicobacter pylori is one of the most common chronic bacterial infections in the world, most infections occurring in developing countries. To determine the frequency of H.pylori infection in our population and its potential role in specific gastrointestinal entities, during a one year period all patients undergoing upper gastrointestinal endoscopy for the evaluation of diverse abdominal ailments were also studied for the presence of this pathogen by gastric biopsy and staining with hematoxylin-eosin and Warthin-Starry. Of the 107 evluated patients (mean age 7,4 y, 58% males), 52(49%) were infected. The infection rate increased with advancing age. Children with recurrent abdominal pain (p=0.04), endoscopic finding of nodular gastritis (p=0.007) and histologic finding of chronic active gastritis(p<0.0001) were more commonly infected. H. pylori was not identified in the two cases of gastric ulcer and 5 of the 11 cases of duodenal ulcer. This data support a role of H. pylori in the syndrome of recurrent abdominal pain in children of developing countries.