Abstract. The effect of ion irradiation on the electrical conductivity of low resistance and high resistance subsurface layers of polycrystalline Li-Ti ferrites is studied. Irradiation was carried out with accelerated Ar  ions with energy E=150 keV and the fluence F = 10 16 ions/cm 2 . It is found that exposure of high-resistance ferrites significantly decreases the activation energy E  and considerably increases the electrical conductivity of the surface layers. The effect of the ion beam on the stated low-resistance characteristics of the samples is much weaker. The observed decrease in the numerical values of E  is due to the decrease in the values of the intergranular potential barrier caused by the exposure. The decrease in the potential barrier difference is due to the decreased degree of the grain boundary oxidation which is caused by preferential desorption of oxygen under the action of the ion beam. The thermal stability of the electrical characteristics of the investigated ferrites subjected to ion radiation-induced modification is determined.