The available knowledge of the oncogenic risks of asbestos, the presentation of some data on the uses of asbestos in railroads, with particular regard to the Italian State Railroads (Ferrovie dello Stato = FS), and the identification of groups at risk because of exposure to asbestos used in railroads are briefly reviewed. The available data in the literature on the pathologic effects of such exposure, and in particular on the onset of mesotheliomas among machinists and other railroad workers, are also summarized. Eighty-three cases, in various Italian regions, of mesothelioma (78 pleural, 4, peritoneal, and 1 pericardial) are reported that are related to the exposure to asbestos used in railroads. Twenty-six of these cases (among which 25 were reported in the Emilia-Romagna region) were submitted to a detailed study at the Bologna Institute of Oncology. Forty-nine cases of mesothelioma occurred among FS workers, in particular machinists; 29 cases occurred among machinists of rolling-stock workshops not belonging to the FS; 3 cases occurred among travelling workers of rolling-stock not belonging to the FS; 2 cases were found in members of the family (a daughter and a wife) of FS workers. This series of cases, together with similar data from the literature, proves the existence and gravity of an actual health risk due to asbestos used in the railroads. On the basis of the available data, the following steps are considered necessary: the adoption of preventive measures, the performance of medical oncological surveillance, the promotion of systematic epidemiologic investigations, and, finally, the placement of greater emphasis on basic research, aimed at generating information on the biological events taking place during the incubation period of the tumors. This information, hopefully, could be used to reduce the biological effect of exposure, and therefore for controlling the neoplastic process before onset of the disease in those who, having been exposed, although healthy, are potentially at risk.