Infrared spectra, molar volumes, ionic conductivities, and transport numbers of silver ions and electrons were measured for glasses in the system AgIAg 2OMoO 3, which contain no ordinary “glass formers”. IR spectra revealed that the coordination number of oxygen to molybdenum is 4 and the glasses with the mole ratio Ag 2O/MoO 3 = 1, or those in the pseudobinary system AgIAg 2MoO 4, contain no condensed macro-anions but only discrete ions of Ag +, I −, and MoO 2− 4. The strong partial covalency is also proved to be present between Ag + and MoO 2− 4 by IR spectra. The molar volume of pseudobinary glasses showed that their glass structure is primarily determined by the ideal mixing and very dense packing of the constituent anions (I − and MoO 2− 4). The conductivity of the glasses, ranging from 10 −2 to 10 −4 ω −1 cm −1 at room temperature, increased exponentially with increasing AgI content, while the total concentration of silver ions remains practically constant; a part of the silver ions are considered to participate in the conduction. The electronic transport number was determined by the Wagner d.c. polarization technique; a glass of total conductivity 1.1×10 −2 ω −1 cm −1 showed the electron conductivity of 8.7×10 −9 ω −1 cm −1. A structure model is proposed for explaining ionic transport in the glasses.