We have fabricated high-efficiency white organic light-emitting devices by using the phosphorescent material fac tris (2-phenylpyridine) iridium [Ir(ppy3)] as a sensitizer. Ir(ppy)3 and the fluorescent dye 4-(dicyanomethylene)-2-t-butyl-6-(1,1,7, 7-tetramethyljulolidyl-9-enyl) (DCJTB) are co-doped into 4,4-N,N-dicarbazole-biphenyl ( CBP)host. N,N-diphenyl-N,N-bis(1-naphthyl)-(1,1-biphenyl)-4,4-diamine (NPB) acts as a blue light-emitting as well as hole-transporting layer. The chromaticity of white emission can be tuned by adjusting the concentration of Ir(ppy)3 and DCJTB. The maximum efficiency and luminance of the device with 3-wt.% Ir(ppy)3 and 2-wt.%DCJTB are 7.5cd A-1 and 12020cd m-2, respectively, which produces fairly pure white emission with the commission inteational De L Eclairage coordinates of (0.33, 0.32) at 10 V.