This book is about the study of association between Helicobacter Pylori (H. pylori) and Chronic Obstructive Pulmonary Disease (COPD). In past years, many studies have been carried out to understand the complex relationship between H. pylori infection and COPD. Few researches have been successful in showing the epidemiologic and serologic evidence for relationship between these two phenomenon. In our study, we aimed to investigate the seroprevalence of Helicobacter pylori in patients with COPD and to determine whether there is an association between H. pylori infection and COPD. The results from our study suggest that there is higher prevalence of H. pylori seropositivity in COPD patients than in non-COPD patients and that HP infection has a positive correlation with the severity of COPD showing the prevalence of HP infection increases with the severeness of COPD. But we were not able to find out the reason for H. pylori infection being related to COPD since our study was carried out in a very small scale and short period of time. To understand the complex relationship between H. pylori infection and COPD, we look forward for a better technical support and a bigger study group.