OBJECTIVE Understanding the chronic inflammatory process that affects the airways of patients with chronic obstructive pulmonary disease (COPD) is an important clue in the search for new therapeutic options. The main inflammatory cells and mediators involved in COPD pathogenesis have been identified, but there is still little knowledge about their mutual interactions that result in the final outcome, that is, structural airway changes and progressive airflow limitation. RESULTS Recent studies created novel theories on the inflammatory pathway in COPD and focused not only on the influence of cigarette smoke but also on other factors initiating airway inflammation. There is evidence that apart from neutrophils and macrophages, eosinophils may play an important role in the pathogenesis of COPD and patients with eosinophilic inflammation may present a distinct phenotype. This may have therapeutic implications. New cytokines (e.g. interleukin 32) involved in COPD pathogenesis have been identified. The increased number of inflammatory cell subpopulations need not necessarily be associated with their increased activity, suggesting their complex role in inducing/sustaining airway inflammation in COPD. The presence of inflammation in the upper airways in the course of COPD has also been found. CONCLUSIONS There are many questions concerning the pathogenesis of COPD yet to be answered. Results of recently published studies show a new approach to airway inflammation in COPD and indicate new interesting directions in COPD research.