Chronic obstructive pulmonary disease (COPD) is an important cause of morbidity and mortality, all over the world. COPD, which was the sixth leading cause of death worldwide in 1990, will become the third one in 2020. COPD is a complex disease, influenced by genetic, behavioral, and environmental factors. The most important factor for developing COPD is tobacco smoke. Also environmental conditions represents risk for developing COPD. Furthermore, diet and a low socioeconomic status are correlated to the disease. Genetic factors, familial history, and childhood lower respiratory tract infections play an important role in the etiology of COPD. Burden of COPD is very high for community. Furthermore, the disease often is under-diagnosed and treated only at advanced stages, whilst it is a substantial health problem even among young adults. This needs to be taken into account by health personnel and decision-makers.