Background and Aim: Eradication of Helicobacter pylori was reported to increase the platelet counts in some H. pylori- positive patients with chronic idiopathic thrombocytopenic purpura (ITP). But the efficacy of the eradication was quite different according to previous reports. The aim of this study was to determine the effect of H. pylori eradication by standard triple therapy, on their platelet counts and the prevalence of H. pylori infection in ITP patients in Pramongkutklao Hospital.Method: ITP patients were assessed for H. pylori infection by 14C -urea breath test. H. pylori positive ITP patients were randomly assigned to either the eradication or the non-eradication group. In H. pylori eradication group, they received standard triple therapy for H. pylori eradication for 1 week. We evaluate the effect of H. pylori eradication on platelet recovery within 6 months after standard triple therapy.Results: Of the 15 ITP patients, 5 (33.3%) were positive for H. pylori. Three patients were received triple therapy for H. pylori eradication. No significant increased in the mean platelet counts after 6 months of therapy.Conclusion: The result from this study could not show the benefit of H. pylori eradication in term of improvement of platelet counts in ITP patients who infected with H. pylori. However further studies with large number of patients are needs to justify the result.