In this paper attempts have been made to prepare superionic glassy electrolytes in the mixed system 30(Cu1-xAgxI)-46.66(Ag2O)-23.33(P2O5), where x = 0.05, 0.1, 0.15, 0.2 and 0.25, respectively, using the melt quenching process. The solid samples were characterized by X-ray diffraction (XRD), differential scanning calorimetry (DSC), Fourier transform infrared (FT-IR) spectroscopy and silver ionic transport number studies. XRD analysis and FT-IR spectroscopic results have provided details regarding the various phases present in the new system and also indicated the formation of composite materials consisting of glassy and crystalline phases. The transport number measurements have indicated the formation of superionic solids having Ag+ ions as the mobile species in the present system.