The nature of current carriers is revealed and the concentration dependence of the true transport numbers of chlorine ions η is studied by the Tubandt method in glasses of the PbCl₂-2PbO · SiO₂ system. It is demonstrated that, in glasses containing up to ∼20 mol % PbCl₂, the electricity transport occurs through protons and chlorine ions. At [PbCl₂] ≥ 20 mol %, the electric current is carried primarily by the chlorine ions. The known crystalline compounds in the PbO-PbCl₂ system are synthesized, and the temperature dependences of their electric conductivity are investigated for the first time. It is found that the introduction of PbCl₂ into PbO is accompanied, first, by an increase in the electric conductivity (to a PbCl₂ mole fraction of ∼0.5), and, then (when PbCl2 single crystals are formed), by its decrease. The temperature-concentration dependence of the electric conductivity for glasses in the PbCl₂-2PbO · SiO₂ system is interpreted in terms of structural-chemical microinhomogeneity of the glass structure due to the selective interaction of components during the glass synthesis.