Abstract: Y3Al5O12:Ce3+ nanophosphor powders were synthesized via a solvothermal method. The pure YAG:Ce crystalline phase was found after solvothermal method at 220 °C/2 h and postannealing at 1150 W using a single-mode cavity of 2.45 GHz microwaves. The average crystallite sizes of powders were in the range of 39–51 nm. The photoluminescence (PL) emission intensity increased with increasing power levels. The microwave annealed sample at 1150 W showed higher PL emission intensity than conventionally annealed sample (1500 °C/4 h).