For patients with haemophilia, gastrointestinal (GI) bleeding is a life-threatening complication and can be caused by the Helicobacter pylori infection. Among children with haemophilia who had visited with GI bleeding, the prevalence of H. pylori infection and the recurrence rate after H. pylori eradication was investigated. Seven children with haemophilia A with hematemesis (age: 5.3-17.0 years) were evaluated for the causes of GI bleeding and the detection of H. pylori. Gastroendoscopy was done to find the bleeding focus and for further evaluation including rapid urease test and mucosal biopsy. Four patients had dyspepsia and abdominal pain for several weeks or months prior to hematemesis. Three patients did not show any symptoms of bleeding. From gastroendoscopy, four patients were diagnosed as duodenal ulcer, one as H. pylori associated chronic gastritis and one as haemorrhagic gastritis. One patient showing a normal finding was diagnosed with adenoid haemorrhage after nasopharyngoscopy. Helicobacter pylori infection was found in four of six patients with GI bleeding (3, duodenal ulcer; 1, H. pylori associated chronic gastritis). The patients with H. pylori infection had an eradication treatment of triple therapy and no recurrence happened. In children with haemophilia, H. pylori should also be considered as an important cause of GI bleeding. The recurrence of the infection and GI bleeding can be prevented with eradication of H. pylori. Screening test for H. pylori would be needed in children with haemophilia in endemic area.