Phase equilibrium diagrams for the systems zinc chloride + silver chloride and zinc bromide + silver bromide were determined by differential scanning calorimetry and X-ray diffraction methods, using high-purity materials and a glovebox for sample preparation. Both equilibrium phase diagrams are of the simple eutectic type. The eutectic points are at 504 K, 53.5 mol % AgCl, and 551 K, 59.4 mol % AgBr, respectively. On the basis of the determined liquidus temperatures, the thermodynamic activities of components in liquid solutions ZnCl2 + AgCl and ZnBr2 + AgBr as well as the integral molar free enthalpies of mixing and the integral molar excess free enthalpies were calculated and discussed in terms of structure of molten salt mixtures.