In an earlier case-referent study from a soft-paper mill with levels of paper dust exceeding 5 mg/m3, an increased mortality was found (OR = 3.8, p less than 0.05) from asthma and chronic obstructive pulmonary disease (COPD) among the employed. Furthermore, other studies on paper mill workers have also indicated an increased mortality from lung cancer. The main objectives of the present case-referent study were to investigate the mortality from asthma. COPD, and lung cancer in two other Swedish paper mills. In these mills, the levels of paper dust have been below 3 mg/m3. The subjects for the study were all men who died between 1961 and 1985 from asthma and COPD (n = 31), respiratory cancer (n = 27), and stomach cancer (n = 33) selected in three parishes surrounding two paper mills. As referents we randomly selected about six times as many men who had died from nonmalignant nonrespiratory diseases in these parishes (n = 550). On the basis of information found in the personnel records in the mills, the men were classified into different occupational categories or as unexposed. No increased risk of asthma or COPD was found among the workers exposed to paper dust. However, it was found that there was significantly increased mortality (OR = 5.7, p less than 0.05) for asthma and COPD among workers in a previous log sorting department. The study also showed a significantly increased risk of lung cancer (OR = 2.1, p less than 0.05) among maintenance workers. There was no increased risk of stomach cancer in the study.(ABSTRACT TRUNCATED AT 250 WORDS)