This Safety Report draws on the requirements of international standards and the recommendations of international organizations as well as on the scientific literature, together with direct experience from a number of IAEA Member States in relation to carrying out representative indoor radon surveys. The need for and the purpose of representative indoor radon surveys are discussed, as well as the factors that must be considered in designing and carrying out such surveys. How the measurement data obtained from indoor radon surveys can be used to develop radon risk maps is also considered. While the Safety Report is focused specifically on national and regional surveys to evaluate average concentrations of radon in dwellings, many of the same considerations also apply to radon surveys for other types of buildings.