New red light-emitting phosphorescent devices using the mixed host of N,N-dicarbazolyl-3,5-benzene [mCP] and bis(10-hydroxy-benzo[h]quinolinato)beryllium [Bebq(2)] doped with 5 vol.% RP411(red phosphorescent dye from SFC Co.) in the emissive layer were fabricated and evaluated according to the mixture ratio of x in a host of mCP(1-x) Bebq(2)(x). Among the fabricated devices, the maximum quantum efficiency was obtained in the device with in a host of x = 0.75 and the highest luminance at a given voltage was obtained in the device with a in a host of x = 0.25. On the other hand, the product of luminance and quantum efficiency showed the best characteristics in the device with a host of mCP(0.5) Bebq(2)(0.5). The peak wavelength in the electroluminescence spectra and color coordinates on the Commission Internationale de I'Eclairage(CIE) chart of the fabricated devices with x 0.25 in a host of mCP(1-x) Bebq(2)(x) were 627nm and (0.66, 0.34), respectively.