(Y1-xGdx)(2)O-3:Eu phosphor particles with dense morphology were prepared by flame spray pyrolysis and the effect of LiCl flux on the crystallinity, morphology, and photoluminescence characteristics of the particles was investigated. All as-prepared particles had monoclinic phase regardless of flux and had different luminescence characteristics from those of commercial Y2O3:Eu particles of cubic phase. The addition of LiCl flux reduced the post-treatment temperature by 300degreesC for phase transformation from the monoclinic phase to the cubic phase. The post-treatment temperature of (Y0.75Gd0.25)(2)O-3:Eu particles for phase transformation decreased from 1100degreesC to 700degreesC when LiCl flux was used. The morphology of the particles was also influenced by the Y/Gd ratio and the LiCl flux. The as-prepared particles had spherical shape and non-aggregation characteristics regardless of Y/Gd ratio and flux. The sphericity of the as-prepared particles prepared without flux was maintained after post-treatment for phase transformation in all Y/Gd ratios. However, LiCl addition promoted the aggregation between product particles. The prepared particles had high photoluminescence intensities comparable to that of the commercial product.