Glass formation and electrical conductivity studies on the AgI-Ag2O-[xV2O5 + (1-x)P2O5], O ≤ x ≤ 1, have been carried out. Glass forming region is found to be within 40 and 66.7 m/o AgI. For similar mole fraction of AgI, quaternary glasses show higher conductivities than the individual ternary systems. Glass transition temperature is found to be almost independent of the V2O5/P2O5 ratio. © 1987.