The Gibbs energies of formation of equilibrium phases are crucial for studies of ore genesis and processing of complex minerals. Thus, the knowledge of thermodynamic properties of equilibrium phases in the binary Ag-Te system will also promote the optimization of the extractive metallurgy of the precious and base metals. A thermodynamic study of the solid two-phase regions of the binary Ag-Te system was made by an EMF technique, using AgI as the solid electrolyte. The intermetallic compounds Ag5Te3 (stützite), Ag1.9Te and Ag2Te (hessite) were synthesized from pure elements and grinded for pressing in to pellets of different compositions. The measurements were made on three galvanic cells; [Ag|AgI| Ag5Te3 + Te], [Ag|AgI| Ag5Te 3 + Ag1.9Te] and [Ag|AgI|Ag1.9Te + Ag 2Te]. Based on the obtained experimental data, the EMF for each equilibrium phase assembly was expressed as a function of temperature in different temperature regions of phase stabilities. In this article, the thermodynamic properties of the ideal stoichiometric equilibrium phase assemblages; Ag5Te3 - Te, Ag5Te3 - Ag1.9Te and Ag2Te - Ag1.9Te, in the temperature range 150 - 351.9 °C, have been studied. The experimental method was illustratively described and the obtained results were analyzed and compared with the literature values.