[en] The climate of Brazil comprises a wide range of weather conditions across a large area and varied topography, but most of the country is tropical. High temperature and humidity levels favour the growth of mould and other fungi in works of art and books. Another big problem found in the conservation of cultural heritage is related to xylophagous insects, especially termites and wood boring beetles. The Multipurpose Gamma Irradiation Facility at the Nuclear and Energy Research Institute (IPEN) of the National Nuclear Energy Commission (CNEN) in São Paulo has been used for disinfestation, disinfection and sterilization of many kinds of cultural heritage materials made of paper, wood, leather, textiles and other materials. These activities have had a significant social impact, and museums, libraries, collectors, conservators and others have benefited from this use of radiation technology. A few these activities are described in this Chapter.