Recent reports have suggested that Helicobacter pylori infection may be a causative agent of adult chronic idiopathic thrombocytopenic purpura (cITP) and antimicrobial treatment may increase platelet counts. As there is limited experience in pediatric age, we investigated the prevalence of H. pylori infection and the effects of H. pylori eradication therapy in a series of children with cITP. Twenty-four children with cITP were investigated for H. pylori infection using the C-urea breath test or H. pylori fecal antigen. In cases of H. pylori infection, antimicrobial treatment was given with amoxicillin, clarithromycin, and proton pump inhibitors. Response was assessed at 6 months and defined as complete (platelet count >150x10/L) or partial (platelet count between 50 and 150x10/L). H. pylori infection was found in 8 patients (33%) and 3 of them showed a response after eradication therapy, but 2 of them relapsed later on. Two patients had a spontaneous increase in platelet count in the group of H. pylori-negative patients. Given that spontaneous improvements in platelet count can occur in children with cITP, we were unable to demonstrate that H. pylori plays a major role in cITP occurring in pediatric age.