Cerium-doped yttrium aluminum indium garnet (YAG: Ce3+) yellow phosphor was prepared by using the co-precipitation method. The impacts of In3+ concentration onto the properties were investigated and analyzed by X-ray diffraction, infrared spectra, scanning electron microscopy, and X-ray photoelectron spectroscopy. The results indicated that the co-precipitation method adopted favored the ultrafine powders and achieved In3+ substitution for part of Al3+, leading to the large crystal plane spacing, and a blue shift occurred in the indium-substituted YAG: Ce3+ emission. (C) 2012 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.