Asbestos is a very relevant medical and social issue, because of its potential dangerous effects on human health. It's present indeed in different environments, because it was widely used in the past. Asbestos is classified as first-class carcinogen, and so labelled with R 45 risk phrase. Exposure to asbestos fibers (both occupational and not) can cause diseases involving mainly the respiratory system. We point out the methods for a correct assessment of the risk from asbestos, with particular reference to current legislation and to the main preventive measures that have to be taken in case of presence of asbestos in a building. A correct prevention has to be carried out through education and information of workers and the use of specific check-lists.