COPD is the fourth leading cause of death in Poland. The disease is diagnosed not early enough. The aim of the study was to establish prevalence of COPD in smokers, inhabitants of Warsaw. Therefore, using local mass media, smokers with at least 10 pack-years history of smoking, over 40 years of age, were invited for a free spirometry. The spirometries were performed during 33 weekends. 3340 subjects (51.8% M and 48.2% F) mean age 57 +/- 13.2 years were examined. Most of them were current smokers (57.8%) or ex-smokers (27%) with a history of 31.9 +/- 18.8 packyears, the remaining subjects (15.2%) declared themselves as a life non-smokers. From all screened 1520 (45.6%) presented airflow limitation (AL). Following ERS recommendations, AL was classified as mild in 27.7%, moderate in 11.1% and severe in 6.8% subjects. One third of examined declared morning cough (36.9%) or sputum production (34.8%), or both symptoms (26.7%). Morning cough (p < 0.05) or cough together with sputum production (p < 0.01) were related to result of spirometry. Subjects aged > or = 40 years with a history of > or = 10 packyears had AL diagnosed in 50.1%, in contrast to younger than 40 years and smoking < 10 packyears in whom AL was detected in 14.3%. In life non-smokers AL was diagnosed in 35.9%. The majority of non-smokers were females (70%), 7.5% declared history of bronchial asthma. The great efficacy of AL detection in targeted population (50%) should be an incentive to perform routine spirometric examination in smokers aged 40+ with a history of 10+ packyears of smoking.