A large number of facilities using radioactive material, including nuclear power plants, research reactors, nuclear fuel cycle facilities, medical facilities and research facilities, are undergoing decommissioning now or will be decommissioned in the near future. Decommissioning of these facilities requires adequate evaluation of safety in accordance with the relevant safety requirements and criteria. This Safety Guide provides recommendations for the development and review of safety assessments for decommissioning activities. It is intended to assist regulators, operators and supporting technical specialists in the application of a graded approach to the development and review of safety assessments.