In the paper, the synthesis and transport properties of the Li7La3Nb2O13 compounds by a solid state reaction are reported for the first time. The optimized conditions to synthesize the Li7La3Nb2O13 ceramics is 1175. degrees C for 24 h with 10% excess lithium salt. The refined lattice constant is 12.8207 angstrom. Qualitative phase analysis by X-ray powder diffraction patterns combined with the Rietveld method reveals garnet type compounds as major phases. Lithium ion conductivity of Li7La3Nb2O13 was studied by AC impedance method. Li7La3Nb2O13 ceramics exhibits the highest total ionic conductivity of 2.2 x 10(-5) S cm(-1) at room temperature with a motional activation energy of 0.39 eV. The SEM images of surface and cross-sections for sintered Li7La3Nb2O13 pellets are shown that their density is also very high. (C) 2017 The Electrochemical Society. All rights reserved.