COPD is currently one of the most important health problems all over the world. The most frequent factor responsible for COPD development is smoking of cigarettes, both active and passive. Other reasons influencing COPD development are occupational exposure to dust, chemical substances, irritant gases. The risk factor is congenital deficiency of α1-antitrypsin (genetic factor). The aim of the paper was to analyse any risk factors influencing development of COPD. The study was performed in 200 people with diagnosed COPD treated between 2005 and 2007. A patient medical history based on a questionnaire prepared for the study was performed in all patients. The study results then underwent statistical analysis. Of the subjects 124 (62%) were males and 76 (38%) were females. Mean age of the males – 66.1 years and of the females – 66.4 years. The main risk factor of the disease in the group studied was cigarette smoking – found in 170 patients (85%), from them 37.5% were current smokers, 47.5% were former smokers. Smoking history of current and former smokers averaged 42 pack-years (range 1-160). COPD was also found in 30 lifelong non-smokers (15%). Exposure to passive smoking at work and/or at home was observed in 175 people (87.5%). The inhalation of hazardous substances in the work environment was reported in 150 of the people studied (75%). Due to the fact that the smoking habit is very frequently found among COPD patients, it seems necessary to intensify actions taken to spread knowledge regarding COPD’s causes and effects, increase anti-smoking education and implement cheap and effective test screening methods.