The glass forming range y for (AgX)(y)((Ag2O)(0.6)(V2O5)(0.4))(1-y) (X=Cl, Br, I) was determined. Composition dependence of ionic conductivity and molar volume was investigated within the glass forming region. First sharp diffraction peak (FSDP) was also investigated for various compositions. Based on these experimental results, it is suggested that doped AgCl and AgBr are dispersed in the openings of the glass network regardless of their concentration, while AgI is dispersed in the AgI region of low concentration, then tend to form ordered structure in the AgI re.-ion of high concentration. The effect of AgI on the medium range order in vanadate glasses is different from that of AgI-AgPO3 glass system, and it is considered that such a distinction arises front the difference of flexibility of the glass network between these glass systems. (C) 2004 Elsevier B.V. All rights reserved.