White light GdPO4:Dy3+ phosphors have been synthesized by solid-state reaction. The phosphors are characterized by X-ray diffraction patterns, room temperature photoluminescence excitation spectra, and room temperature photoluminescence (PL) emission spectra. Under host Gd3+ sensitization and direct Dy3+ 4f-4f excitation, the activator Dy3+ exhibits bright white light. The dependence of PL spectra on the activator Dy3+ doping concentration (from 0.3 to 2 mol %) and calcining temperature (800, 900, 1000, 1100, and 1200 degrees C) are also studied. The study suggests that the GdPO4:1 mol % Dy3+ phosphor annealed at 1000 degrees C for 2 h with host Gd3+ 275 nm sensitization has the strongest white light. The calculated chromaticity coordinates with 275 nm radiation of all the phosphors fall well in the white region of 1931 Commission International de I'Eclairage diagram. These experimental results indicate that the Dy3+ activated GdPO4 is a promising white light material and has potential applications in lighting technology. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3517458] All rights reserved.