Helicobacter pylori is an established cause of chronic-active gastritis in both adults and children. However, it is unclear whether H. pylori causes specific clinical symptoms. Therefore, the spectrum of clinical symptoms associated with H. pylori infection was studied in consecutive symptomatic children undergoing diagnostic endoscopy at two pediatric centers, using a structured questionnaire. In Toronto, Canada, 86 of 97 eligible children were enrolled into the study and in Limerick, Ireland, 24 of 29 were enrolled. The frequency of biopsy-confirmed H. pylori infection in Limerick, 16 of 24 (67%), was fivefold higher than in Toronto, 11 of 86 (13%, P = 0.0001). The two study populations were comparable in clinical presentation and duration of symptomatology and did not differ in age (11.9 +/- 3.5 and 11.6 +/- 2.0 years, respectively). Within both study populations H. pylori infection was not associated with specific clinical symptomatology, including duration of abdominal pain, location of pain, and history of melena or vomiting. H. pylori was positively associated with hematemesis in the Limerick group. These findings demonstrate that H. pylori infection in children is not associated with specific clinical symptomatology across varying geographical locations.