BACKGROUND Several studies showed some chronic idiopathic thrombocytopenic purpura (ITP) patients with complete platelet recovery after Helicobacter pylori (H. pylori) eradication and cited the cause of persistent thrombocytopenia as inability to eradicate H. pylori. So we studied H. pylori infection status in pediatric ITP patients at diagnosis and address whether such infection played a role in the development of childhood ITP. METHODS We compared H. pylori infection status by stool H. pylori antigen test of an ITP group including 32 childhood ITP patients at diagnosis from September 2004 to June 2006 and a control group including 30 unselected patients with no history of thrombocytopenia seen consecutively with clinical manifestations of pharyngotonsillitis, bronchitis, or bronchopneumonia in our ward during a one-month span. We further analyzed parameters between H. pylori infection-positive (H. pylori(+)) and H. pylori infection-negative (H. pylori(-)) childhood ITP patients. RESULTS The H. pylori-positive (H. pylori(+)) rate was 19% in the study group and 17% in the control group, with not statistically significant difference. As for the characteristics and treatment response about H. pylori status, they were also not statistically different. Although the ratio of chronic ITP cases showed higher tendency in H. pylori(+) patients (2/6) than the H. pylori(-) ones (3/26), it was not statistically significant. CONCLUSIONS It seems that H. pylori infection played a minor role in the development of childhood ITP in this small-scale study. A large-scale study is necessary to further confirm the relationship between H. pylori infection and the development of childhood ITP.