A rare earth double perovskite oxide barium cerium tantalate, Ba2CeTaO6 (BCT) is synthesized by solid-state reaction. The X-ray diffraction pattern of the sample at room temperature (25 degrees C) shows monoclinic structure, with the lattice parameters, a = 9.78 angstrom, b = 9.02 angstrom and c = 4.27 angstrom and beta = 93.8 degrees. A scanning electron micrograph shows the formation of grains with average size similar to 2 mu m. Impedance spectroscopy is applied to investigate the ac electrical properties of BCT in a temperature range from 303 to 673 K and in a frequency range from 100 Hz to 1 MHz. Complex-impedance-plane plots show grain contribution for BCT. The frequency-dependent electrical data are analyzed in the framework of the conductivity and modulus formalisms. The frequency-dependent conductivity spectra follow a power law. The conductivity at 110 Hz varies from 3.5 x 10(-7) S m(-1) to 1.2 x 10(-2) S m(-1) with increasing temperature from 303 to 673 K, respectively. The scaling behaviour of M" and Z" suggest that the relaxation describes the same mechanism at various temperatures. (C) 2011 Elsevier Ltd. All rights reserved.