In the present study, polycrystalline Li-Si ferrites with the general chemical formula Li0.5 + 0.5xSixFe2.5 - 1.5xO4, (where; x = 0.0, 0.1, 0.2, 0.3, 0.4, 0.5 and 0.6) were prepared by high energy ball milling (HEBM) technique. The effect of Si addition on the structure and electrical properties of lithium ferrite were explored. X-ray diffraction analysis indicated that all the samples are formed in cubic spinel structure. The lattice parameter was found to decrease smoothly with increasing silicon content The average grain size 'D' was determined from the scanning electron microscope (SEM) micrographs and it was found to decrease with increasing silicon substitution. In the infrared spectra, two fundamental absorption bands were observed, which are attributed to the intrinsic vibrations of tetrahedral and octahedral complexes, respectively. The wave number of the two bands shifts slightly towards higher frequency side with Si addition. The dc electrical conductivity, studied from room temperature up to 960 K in static air, increases linearly with temperature indicating the semiconducting nature of the samples. The possible mechanism for the influence of silicon substitution on the electrical properties of lithium ferrites was discussed on the basis of the hopping and small polaron models. (C) 2017 Elsevier B.V. All rights reserved.