Introduction - Nearly 20% of pleural mesotheliomas in men and 60% in women occur in people who have never been occupationally exposed to asbestos. In these individuals, as in those with non-pleural mesothelioma, it is important to investigate non-occupational sources of asbestos exposure and exposure to risk factors for mesothelioma other than asbestos. The objective of this study is to describe potential non-occupational exposures to various mesothelioma risk factors among individuals with mesothelioma who have no or possible occupational exposure to asbestos. Materials and Methods - As part of the DO-Mesothelioma pilot study, conducted in eight French regions, 78 subjects with no or possible occupational exposure to asbestos were included. The diagnosis of mesothelioma (all sites) was made between 2013 and 2015 and reported via mandatory reporting (DO). Potential exposures to asbestos, as well as to other mesothelioma risk factors suggested in the literature, were assessed through expert review of questionnaires and a geographic information system. For these 78 subjects, the study describes non-occupational exposures related to proximity to occupationally exposed individuals (para-occupational exposures), DIY activities, the living environments themselves, proximity to environmental sources, possible occupational exposures, as well as medical and therapeutic histories. Results - Among the 78 subjects, 53% may have been exposed due to the proximity of their living environments to environmental sources (<2 km), 46% through para-occupational exposures, 22% through possible occupational exposures to asbestos, 17% through exposures at home, and 17% through exposures via home improvement activities. Furthermore, 20% were at risk of non-occupational exposure to mineral wool. Ultimately, 90% of the study subjects had at least one risk factor for non-occupational exposure to asbestos and/or mineral wool, while 10% of the subjects had no known exposure to fibers. The percentage of cases involving para-occupational exposure was higher among women than among men, whereas potential occupational exposure or exposure related to DIY activities was more common among men. One in 10 subjects had been exposed to ionizing radiation, either occupationally or for medical purposes. Conclusion - This pilot study assessed non-occupational exposures to asbestos and other mesothelioma risk factors within the framework of the National Mesothelioma Surveillance Program (PNSM) and the DO. The method developed will be applicable to a larger number of PNSM subjects and, ultimately, within the National Mesothelioma Surveillance System (DNSM). It has helped to support the hypothesis regarding the possible role of para-occupational exposure, DIY activities, or residential proximity to potential sources of environmental asbestos emissions in individuals with mesothelioma (both pleural and extrapleural) for whom occupational exposure was either absent or possible.