Background Otitis media with effusion (OME) is a common pediatric disease,but its pathogenesis remains uncertain.The relationship between OME and Helicobacter pylori (HP) is currently being studied,and a relationship has not yet been confirmed.The purpose of this study was to show that a relationship does exist between HP and OME.Methods The study consisted of 60 patients who were diagnosed with OME and had ventilation tube insertions with or without an adenoidectomy.This study included an additional 30 patients who had only received an adenoidectomy without being diagnosed with OME.The effusion samples were analyzed with polymerase chain reaction (PCR) and the campylobacter-like organism (CLO) test.The adenoid tissue samples were analyzed with the CLO test.Results Eighteen patients among the 60 patients (30％) tested positive for HP.In the cases with adenoids,15.6％ of the OME patients and 13.3％ of the adenoidectomy only patients were positive for HP.There were no differences between the prevalence of HP in the adenoids of OME patients and the patients without OME.Conclusion HP can be considered one of the causes of OME.