Gold nano- and submicro-particles were prepared on indium tin oxide (ITO) substrate by methods of sputtering deposition (SD), self-assembly (SA) and electrochemical deposition (ECD). The electrocatalytic activity of these gold particles toward CO oxidation was systematically studied using cyclic voltammetric (CV) technique. It was found that the method used to prepare gold catalysts had great effect on their catalytic activity and stability for CO electrooxidation. Electrodeposited Au particles exhibited a higher activity and better stability than particles prepared by SD and SA methods. The distinct activity and stability of gold particles prepared by ECD was believed to be due to the strong "support effect" arising from the intense interaction between gold particles and the substrate. An electrochemical dissolution process of gold was revealed on all kinds of gold particles after long-term CO electrooxidation. The dissolution of Au in alkaline solution was proposed as the primary origin for the deactivation of gold catalysts. (C) 2013 Elsevier B.V. All rights reserved.