Magnesium ion containing gel polymer electrolytes based on polyacrylonitrile (PAN) have been synthesized and characterized using ac impedance measurements. The electrolyte composition having the highest room temperature conductivity was found by varying the ratios propylene carbonate/ethylene carbonate (PC/EC) and PAN/Mg(ClO4)(2). The corresponding composition was 18 mol% PAN:64 mol% EC:14 mol% PC:4 mol% Mg(ClO4)(2). The ac conductivity measurements were carried out from room temperature up to 70 degreesC with blocking (stainless steel) electrodes. The room temperature conductivity is 3.2 x 10(-3) S cm(-1) and the activation energy is 0.24 eV over the temperature range used. The high conductivity and the low activation energy of the material could possibly be due to the liquid electrolyte, Mg(ClO4)(2) in EC/PC trapped in a matrix of PAN, as suggested by previous workers. According to dc polarization measurements, the gel electrolyte appears to be predominantly an anionic conductor. (C) 2004 Elsevier Ltd. All rights reserved.