FSDP measurements were performed by X-ray diffraction, neutron diffraction and elastic neutron scattering experiments for AgI-Ag2O-V2O5 and some of AgBr-Ag2O-V2O5, AgCl-Ag2O-V2O5 and AgI-AgPO3 glasses at room temperature. FSDP observed by X-ray diffraction is due to the density fluctuation of the network structure. Composition change of this FSDP profile for AgI-Ag2O-V2O5 glasses corresponds to those of the ionic conductivity and the molar volume. New FSDP was found in the high AgI region of AgI-Ag2O-V2O5 system by elastic neutron scattering. FSDP observed by neutron scattering suggests the formation of medium range order of doped AgI in highly AgI-doped glasses. (C) 2004 Elsevier B.V. All rights reserved.