The purpose of the study was the determination of prevalence of chronic bronchitis in people older than 55 years in rural and industrial areas. 569 people over 55 years old living in central Greece were studied. A protocol was completed for each patient that included smoking habits, job, age, weight, drugs used for respiratory system and symptoms. A chest radiograph was taken for each patient. Each patient was submitted to three trials of dynamic spirometry. The best results were used for the study. The patients who complained of expectoration for three months for two continuous years and had obstructive pattern of lung function were diagnosed with chronic bronchitis. 9.6% of the subjects in rural area and 17.1% in industrial area were diagnosed with chronic bronchitis. Half the COPD patients never visited a doctor for this specific problem and were diagnosed for the first time. One out of three examined people had abnormal lung function. Consequently, more than one out of ten people older than 55 years have chronic bronchitis. Industrial exposure seems to double the risk for chronic bronchitis.