This report is the result of an analysis of the medical records of 124 patients presenting with a malignant pleural mesothelioma. Information about asbestos exposure was available in 104 of them, which appeared to be positive in 95 (91%). The median duration of exposure was 34 yrs. The median latent period was 41 yrs. The median survival was 11 months while different ways of treatment could not prolong survival. The most common radiologic findings were pleural effusions, while in some patients contralateral effusions or pleural thickening was found. Pleural plaques or asbestosis were seen in a minority of the patients. In this series a relatively high percentage of mixed type mesotheliomas was found (56%). Large biopsies will often show both epithelial and connective tissue type elements. Concerning diagnostic procedures we recommend beginning with cytology of pleural fluid, which can easily be obtained together with an Abrams biopsy. If this does not give a definite diagnosis thoracoscopy or thoracotomy will be indicated.