The paper provides a qualitative review of the effects of fast neutron irradiation on the mechanical behavior of materials used in the construction of Fast Breeder Reactor Core Components. The paper is presented in three sections. First, effects of preirradiation on the strength, ductility, elastic moduli, thermal creep, creep-rupture, and fatigue are discussed. Second, the phenomenon of irradiation induced swelling is explained and the effects of temperature, cold work, and stress on swelling are presented. Third, irradiation creep is defined and the effects of temperature, stress, and cold work on irradiation creep are discussed. The review is based on the most recently available experimental data on austenitic stainless steels.