Electrochemical reduction of CO2 under high pressure in cold methanol (243 K) medium containing LiClO4 as supporting electrolyte was studied using Cu wire electrode. The major reduction products formed were methane, CO, ethylene and HCOOCH3. The experiments were carried out at different operating potential ranging from -3.0 to -4.0 V and the results were discussed in terms of their faradaic efficiencies. The different applied potentials employed invariably favored methane formation in the presence of Li+, at 243 K and 4 atm and, among which, the most negative potential (-4.00 V) showed relatively better efficiency than the less negative potentials. However, the H-2 formation, an undesirable reduction product, was found to be as high as 60.2% at -4.00 V. The effective formation of methane and CO were discussed in terms of influence of the size of the cation of the supporting electrolyte used. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.