YAG:Tb particles with sphericity, fine size and non-aggregation characteristics were prepared by a spray pyrolysis process. The characteristics of prepared particles such as crystallinity, morphology, and photoluminescence were compared with those of commercial YAG:Tb phosphor particles. The prepared particles without using flux had higher crystallinity than that of the commercial products and maintained its sphericity and non-aggregation characteristics even after post-treatment at 1400 degrees C for 5 h. The mean size of the prepared particles was 0.94 mu m. For the maximum brightness of YAG:Tb particles, the doping concentration of Tb was 2.5 at.% and the optimum post-treatment temperature was 1400 degrees C. The photoluminescence brightness of particles post-treated at 1400 degrees C was in the same order comparing to that of the commercial product. (C) 1999 Elsevier Science Ltd. All rights reserved.