Lithium ion was successfully introduced into La1/3NbO3 with an A-site-deficient perovskite-type structure. The crystal structure and transport properties of La1/3LixNbO3 were investigated as a function of Li content (x = 0-0.59). The lattice parameters of La1/3LixNbO3 with an orthorhombic cell were enlarged with increasing Li content for x less than or equal to 0.3, and the structure was transformed to a pseudo-tetragonal cell for x = 0.44. The temperature dependence of electrical resistivity gradually changed from insulating to metallic with increasing x, and thermoelectric power measurement indicated that the carriers were electrons. In X-ray photoelectron spectra of the incorporated samples, Nb-3d(4+) peaks appeared in addition to Nb-3d(5+) peaks, which was consistent with the change of the transport properties. In spite of the success of metallization, no diamagnetic signal indicative of supercondcutivity was observed in La1/3Li0.59NbO3 down to 1.8 K. (C) 2004 Elsevier Ltd. All rights reserved.