The structural and luminescent properties of Y 3 Al 5 O 12 /Y 4 Al 2 O 9 :Ce 3+ (0.1%)–Pr 3+ (0.1%) –Cr 3+ (trace impurities) nanophosphors synthesized by a simple hydrothermal method were studied. The crystalline phase was composed of Yttrium Aluminum Garnet (YAG) and Yttrium Aluminum Monoclinic (YAM) depending on the ammonia concentration and annealing temperature. Ammonia increased the stabilization of YAG from 55wt% to 63wt% in the samples annealed at 900°C, and an increment of 83% of the overall emission under 460nm excitation was observed. Quenching of the emitted signal after annealing at 1100°C was observed in spite of single YAG crystalline phase stabilization, due to the formation of Ce 4+ , Pr 4+ , and color centers. In addition to the green–yellow emission from Ce 3+ , all samples present a broad red emission band produced by the relaxations from the broad band 4 T 2 toward the 4 A 2 energy level of Cr 3+ impurities, under 340nm excitation. By taking advantage of this broad green–yellow–red emission and using a blue dye, white light with CIE coordinates of (0.30, 0.36) under 340nm excitation was produced.