A case-control study was carried out on 41 surgical and 106 autopsy histological tissue samples of lung cancer in men, in order to investigate the relationships between asbestos exposure and cell type of pulmonary carcinoma. Both occupational history (obtained by interviews of surgical patients or of the next-of-kin for deceased subjects) and lung asbestos body content (determined by optical count after hypochlorite digestion and membrane filtration of lung tissues) were considered as asbestos exposure indicators. No significant relationships were found in the surgical series after adjustment for smoking. The autopsy series showed a trend towards an association between lung adenocarcinoma and asbestos exposure indicators and a markedly higher agreement between the 2 kinds of indicators than that observed in the surgical series.