The international project on evaluation and demonstration of safety during decommissioning of facilities using radioactive material (DeSa), launched by the IAEA in 2004, helps to ensure that specific guidance on the safety assessment in the context of the decommissioning of nuclear facilities is provided. This publication presents the outcomes of the work carried out in fulfilling the action plan through the DeSa Project. The main features of the process have been summarized and overall recommendations on producing, reviewing and implementing the safety assessment have been made. They are supported by specific recommendations contained in Annexes I–III.