Background and aim of the work: Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality worldwide. Many studies reported a high prevalence of Helicobacter pylori (H. pylori) infection in COPD patients and this may have a role on severity of COPD. To estimate impact of H. pylori infection on exacerbation and severity of COPD. Patients and Methods: A prospective observative study was conducted for one year and included 142 well controlled COPD patients. Participants were classified into two groups; group 1 which included 72 COPD patients with +ve H. pylori infection and group 2 which included 70 COPD patients with -ve H. pylori infection. All participants were submitted to full clinical examination, routine laboratory investigations, CXR, arterial blood gases analysis, spirometry, H. pylori serology and stool antigen and COPD assessment test (CAT). Patients were followed monthly for at least three months. Results: High significant statistical differences were found between both groups regarding; FEV1, FVC, PH, PaO2, which were lower in group 1 when compared to group 2. While CRP, CAT score, PCO2, HCO3 were significantly higher in group 1. COPD severity was higher in group 1 when compared to group 2 where the sever and very sever COPD cases were more abundant in group1. Conclusion: H. pylori infection adds an inflammatory burden in the COPD patients by increasing their CAT and number of COPD exacerbations per year.