Purpose: The purpose of this study was to assess the frequency of H. pylori infections in children with upper gastrointestinal complaints. This study was also aimed to evaluate the usefulness of diagnostic methods and to assess the effectiveness of treatment. Study design Cross sectional study: Place & duration of study: Pediatrics unit, Civil Hospital, Karachi for 36 Months, (Aug. 2001 to Jul. 2004). Patients & methods: Upper gastrointestinal endoscopy and gastric mucosal biopsy were performed on 129 children who visited the OPD or were admitted to the Department of Pediatrics Dow University of health sciences & Civil Hospital Karachi or directly referred from other Pediatric facilities of the province from, Aug. 2001 to Jul. 2004 due to abdominal complains or upper gastrointestinal bleeding. All patients who under went upper GI endoscopy examination were analyzed retrospectively from record. Results: Out of 129 biopsies, 70 were positive for H.Pylori culture and histopathological evidence. Conclusions: The prevalence of H. pylori infection in children presenting with abdominal complaints was 54%. These children underwent for upper GI endoscopy who were referred due to abdominal complains. This is a very high rate of infectivity and physicians in general and pediatricians particularly need to keep a high index of suspicion for this organism, so that proper treatment for children with abdominal complaints might lower the incidence of peptic ulcer diseases or gastric cancer with advancing age.