AbstractRadon, a natural radioactive element present in air, soil and water, has been proved to be related to lung cancer: according to the US EPA, nearly 10% of lung cancer deaths are attributable to radon, while Spanish studies estimate this figure is about 5%.Hence, a wide number of research works have been carried out worldwide to determine the underlying factors, existing risk and remediation measures.In Spain, MARNA project pointed out the high radiation levels in Galicia. The main studies regarding Galician radiation are explained, as well as the principal remediation measures applied to reduce radon exposure at home.