Eu3+-doped red-emitting phosphors of double perovskite Ba3Y2WO9 were synthesized by the solid-state reaction. The phosphors were characterized by X-ray powder diffraction. The luminescence properties, e. g., the excitation and emission spectra, luminescence decay times and CIE coordinates were investigated. The phosphors can be efficiently excited by near UV light to realize an intense red luminescence corresponding to the electric dipole transition D-5(0) -> F-7(2) of Eu3+ ions. The double perovskite oxide was investigated by the site-selective emission spectra and the luminescence decay curves in the D-5(0) -> F-7(0) region using a pulsed, tunable, narrowband dye laser. It is suggested that Eu3+ ions have three different crystallographic sites in this host. The site assignments of Eu3+ ions were discussed on the base of both optical spectroscopy and structural analysis. This is helpful to understand the occupation of rare earth ions doped in this perovskite structure. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3585838] All rights reserved.