The relation of smoking to chronic lung disease has been documented in several studies. Several conclusions have been drawn about the type of smoking associated withdisease, including inhalation, filter tip use, and reduction in smoking. These factors were examined in a community epidemiologic study of chronic obstructive lung diseases. It was found that the community population exhibited greater filter tip use and higher rates of exsmoking than often seen elsewhere. Smoking habits and the changes in smoking habits over time were related to physician-diagnosed emphysema and/or chronic bronchitis, but not asthma. Some relation was seen also with present heart trouble. There was dose-relationship to pack-years of smoking in both present and ex-smokers. There were more ex-smokers among males. Most male ex-smokers quit due to symptoms. Ex-smokers were found to have high rates of diagnosed disease but reduced rates of symptoms. The incidence of diagnosed disease was found to be associated with smoking, both in intensity and duration. Changes in smoking over time were found to be correlated with symptomatology.