[en] Based on several publications (notably UNSCEAR publications), this issue proposes an overview of sources of exposure to natural radioactivity (average value, noticeable variations, importance of exposure conditions; irradiation from cosmic and telluric origins, case of radon, distribution among the different sources). It also comments results of studies of biological and health effects, and of studies which more particularly addressed the case of radon. It also evokes regulatory evolutions regarding natural radioactive materials used in the industry.