AbstractThe four parties to the Agreement on Co-operation in the Engineering Design Activities for the International Thermonuclear Experimental Reactor (ITER) have successfully completed 6 years of collaborative work, the results of which are encapsulated in the ITER Final Design Report, Cost Review and Safety Analysis, (FDR) and supporting technical information, including the output from ongoing major technology R&D projects. The FDR provides a detailed, complete and fully integrated engineering design of ITER, including the latest assessment of ITER plasma performance and safety characteristics and of its cost which remains as originally agreed. The technical results provided should have been sufficient to allow a construction decision by the parties who have now found the investment too large to be affordable. Further development of the project, aimed at enabling a future possible decision on construction, includes design work to achieve cost reduction by reducing performance in ways that will still allow to meet ITER overall programmatic objectives; to adapt the design to specific site characterisations; and to prepare for regulatory procedures.