The solid electrolyte Li(1.3)Zr(1.4)Ti(0.3)A(0.3)(PO4)(3) compound was synthesized by a solid-state reaction. The ceramic samples were sintered 1, 2 and 3 h and studied by X-ray and complex impedance spectroscopy in the frequency range from 10(6) to 1.2 x 10(9) Hz in temperature range from 300 to 600 K. The investigated compound at room temperature belongs to rhombohedral symmetry (s.g. R (3) over barc) with six formula units in the lattice. Two regions of relaxation dispersion were found. The dispersions are related to the fast Li+ ion transport in the grain and grain boundaries of ceramics. Varying of the sintering time affects the density of the ceramics, the values of total conductivity and its activation energy. The values of grain conductivity, its activation energy, and relaxation frequency in grain, dielectric permittivity and dielectric losses are independent from sintering duration of the ceramics. The value of activation energy of grain conductivity and activation energy of relaxation frequency is the same. That can be attributed to the fact that the temperature dependence of the grain conductivity is caused only by the mobility of Li+ ions, while a number of charge carriers remains constant with temperature. (c) 2006 Elsevier Ltd. All rights reserved.