Na2CO3 flux was introduced in the preparation of phosphor particles by spray pyrolysis to improve the photoluminescence (PL) characteristics of (Y0.5Gd0.5)(2)O-3:Eu phosphor particles, The phosphor particles directly prepared by spray pyrolysis at 1300 degreesC from solutions with 20 wt% Na,CO, nux had the highest PL intensity, which corresponded to 130% of that of particles prepared from solution without flux. On the other hand, the maximum PL intensity of the annealed particles, which were as-prepared at 900 degreesC and posttreated at 1200 degreesC for 3 h, was obtained from a solution with 5 wt% Na2CO3 flux, The maximum PL intensity of particles directly prepared by spray pyrolysis without posttreatment was 86% of that of posttreated phosphor particles. Na2CO3 flux was also important in control of morphology of (Y0.5Gd0.5)(2)O-3:Eu phosphor particles.