AbstractDesign loadings and potential mechanical damage in ITER in-vessel components are enumerated. Design by analysis requirements for ITER blanket and divertor are discussed in the light of the decreasing ductility of the structural material as a function of the neutron fluence. The applicability and limitations of the ASME Boilers and Pressure Vessels Code, Section III to ITER components are discussed. The design rules from fission reactor core components are reviewed for potential application to ITER.