Abstract The electrochemical reduction of CO2 at a Cu electrode was investigated in a methanol-based electrolyte using such potassium supporting salts as CH3COOK, KBr, KI and KSCN at extremely low temperature (30C). The main products obtained from CO2 by the electrochemical reduction were methane, ethylene, ethane, carbon monoxide and formic acid. The maximum Faradaic efficiency of ethylene was 19.9% in KI/methanol-based catholyte at 3.0V vs. Ag/AgCl saturated KCl. The best methane formation (27.0%) was obtained in CH3COOK/methanol electrolyte at 3.0V. In the system containing a potassium halide, the efficiency of hydrogen formation, being a competitive reaction against CO2 reduction, was suppressed to less than 8.1%. The product selectivity of the electrochemical reduction of CO2 in methanol was greatly affected by the anionic species. This research can contribute to the large-scale manufacturing of useful organic products from readily available and cheap raw materials: CO2-saturated methanol from industrial absorbers (the Rectisol process).