The ion transport properties of perovskite-type compounds, La1/3-xLi3xTaO3, (La1/4Li1/4)(1-x)Srx/2TaO3 and R1/4Li1/4TaO3 (R = La, Nd, Sm, Y), were investigated by d.c. measurement and the scaling analysis of conductivity spectra. These compounds were confirmed to be lithium ion conductors and to behave as strong electrolytes. As the exponent of the universal power-law is reasonably related to the average valence of the A-site cation, immobile A-site cations seems to have an influence on the lithium ion transport process. (C) 2000 Elsevier Science B.V. All rights reserved.