We have fabricated 0.2Pb(Mg1/3Nb2/3)O-3-0.8Pb(Zr0.475Ti0.525)O-3 [PMN-PZT] ceramics doped with various amounts of Li2O (0, 0.05, 0.1, 0.2,0.3 wt.%) using the columbite precursor method. The effects of Li-doping on the conduction behavior of PMN-PZT ceramics are discussed in relation to the low frequency dielectric dispersion and frequency domain measurement. The Li-doped PMN-PZT ceramics sintered at 950degreesC showed a sufficient densification with large dielectric constant and low dielectric loss. The incorporation of Li+ ion in PMN-PZT ceramics led to an appreciable reduction in electrical conductivity and further enhanced the ferroelectric and piezoelectric properties. The activation energies of PMN-PZT + xLi(2)O (x = 0, 0.05, 0.1, 0.2, 0.3 wt.%) ceramics calculated from ac conductivity measurement using the Arrhenius relation were 1.05, 1.25, 1.27, 1.38 and 1.41 eV, respectively. The conduction behavior is examined in the low frequency and high temperature region and the results are discussed in detail through crystal defect mechanism. (C) 2004 Elsevier B.V. All rights reserved.