This study included 97 subjects with parenchymal and/or pleural asbestosis and 100 controls. Data analysis included medical and work histories, X-ray clinical examination, and the measurement/calculation of ventilatory lung functions VC, FVC, FEV1,FEV1/VC and FEV1/FVC. Of 97 subjects with asbestosis, 30 (31%) were diagnosed parenchymal fibrosis, 33 (34%) pleural fibrosis, and 34 (35%) parenchymal and pleural fibrosis combined. These subgroups did not differ in smoking habit. All subjects with asbestosis showed symptoms of dyspnoea; two thirds showed dyspnoea on exercise and one third at rest as well. In contrast, only one third of controls showed dyspnoea on exercise only. All ventilatory lung functions were lower in subjects with asbestosis than in controls (P < 0.01), except for FEV1/FVC (P > 0.05). Slight, yet clinically significant drops in ventilatory function were observed in subjects with pleural (VC 79.73%; FVC 75.09%; and FEV1 78.52%) and combined asbestosis (VC 78.21%; FVC 75.01%; and FEV1 77.50%), while ventilatory changes in subjects with parenchymal asbestosis were clinically significant only for FVC (79.60%). It was not possible to discriminate between the effects of age and exposure duration in subjects with pleural and combined asbestosis.