An In2O3 single crystal was successfully grown electrochemically applying the In3+ ion conducting In-2(MoO4)(3) solid electrolyte. In the ln(2)(MoO4)(3) solid electrolyte, only In3+ ion species can migrate in the molybdate solid, and by the DC electrolysis, the In3+ ion species continuously supplied and deposited on the cathodic surface of the electrolyte. Since the single crystal growth can be regulated by the electrolysis condition, the crystal size can be intentionally controlled by adjusting the electrolysis period. This is a new way of single crystal growth with a certain crystal size as expected. (C) 2004 Elsevier B.V. All rights reserved.