Bulk-ordered nanocrystalline FeAl intermetallic compound with a grain size of 35nm was prepared using severe plastic deformation. Nanocrystalline and coarse-grained counterparts with a grain size of 160nm were subjected to 1.5MeV Ar ⁺ ion irradiation at room temperature. Enhanced irradiation resistance of nanocrystalline FeAl has clearly been identified by means of grazing-incidence X-ray diffraction and Mssbauer spectroscopy. At the identical damage dose, the nanocrystalline FeAl retains long-range ordering in the B2-superlattice structure, while the coarse-grained state becomes already substantially disordered. The present experimental studies verify that fully dense ordered intermetallic alloys are promising candidate materials for radiation environments.