The effect of irradiation by 300-keV Ar+ ions on the properties of electrochemically produced porous silicon is studied at doses of 5 x 10(14)-1 x 10(16) cm(-2). Raman scattering and photoluminescence data are used to show that the radiation hardness of porous silicon layers is substantially greater than that of single crystal silicon. (C) 1997 American Institute of Physics.