Eu3+-Y3+ codoped tin-doped indium oxide (ITO) powders were fabricated by the sol-gel method. The doping concentration of Sn4+ ions was fixed at 10 mol%. According to the powder X-ray diffraction and X-ray photoelectron spectroscopy analyses, few Y3+ (<= 2 mol%) ions can dissolve in Sn4+ (10 mol%)-doped In2O3 lattice to form YySnzIn2-y-zO3 solid solution but more Y3+ doping (> 2 mol%) results in the segregation of excess Y3+ ions to form Y2O3. Therefore, the Eu3+-Y3+ (> 2 mol%) codoped ITO powders are composed of a mixture of EuxYySnzIn2-x-y-zO3 and EuwY2-wO3 phases. The resulting Eu3+-Y3+ codoped ITO powders exhibit enhanced red 611 nm emission (D-5(0)-> F-7(2) transition) by adding more Y3+ ions. The D-5(0)-> F-7(2) transition corresponding to the f-f transitions of Eu3+ ions and the Eu-O charge transfer occur at the strong absorption of 467 and 237 nm, respectively. However, the conductivity of Eu3+-Y3+ codoped ITO powders is deteriorated by the more addition of Y3+ ions due to the formation of more insulating Y2O3. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.042204jes] All rights reserved.