Abstract. Nuclear design for ITER having an impact on components, equipment, and materials, must conform to established requirements, and must be fully traceable to valid data, and capable of withstanding detailed technical reviews. According to the Management and Quality Program that is being established in the ITER project, nuclear data used for neutronic calculations must be verified and validated prior to use in ITER design. Extensive work of validation and verification FENDL-1 and FENDL-2.0 libraries for neutronic calculations was performed during the ITER R&D activities through ad hoc benchmark experiments performed on mock-ups of ITER components at 14 MeV neutron generators. In particular, this paper presents the validation of the latest version FENDL-2.1 using the existing benchmark experiments carried out at the FNG 14 MeV neutron generator at ENEA Frascati.