This study focuses on the spread of mesothelioma in Siena. The population consisted of 30 patients. The diagnosis was made through histopathological and immunoistochemical or cytological and immunoistochemical analysis. The association between malignant masothelioma and exposure to asbestos was deduced by the occupational history. The mesothelioma was noted both in traditional industries and other jobs such as the chain of manifacture, plumbers, electricians, carpenters, installers of asbestos insulation and construction workers. Thus it is possible to find other malignant and nonmalignant asbestos-related diseases more frequently than mesothelioma. There is an evident risk in rebuilding, so the development of new cases due to these exposures is expected.