Silverphosphotellurate (SPT) quaternary fast ionic conducting (FIC) glasses of compositions Agl-Ag2O-[(1-x)P2O5 + xTeO(2)], x = 0.0 to 1.0 in steps of 0.1, were prepared by melt quenching. All SPT compounds were characterized by X-ray diffraction and the amorphous nature of the samples was confirmed. The structure of all compositions was examined by Fourier Transform Infrared Spectroscopy. The glass transition temperature (T-g) was determined for all SPT samples, using differential scanning calorimetry. Complex impedance measurements were made on all glasses in the frequency range 40 Hz to 100 kHz. Impedance data were analyzed using Boukamp equivalent circuit software and the bulk conductivity was obtained. The highest conductivity (sigma = 1.59 * 10(-2) S/cm) was shown by the composition 60% Agl - 26.67% Ag2O - 13.33% (0.3P(2)O(5) + 0.7TeO(2)). (C) 2004 Kluwer Academic Publishers.