Electric conductivity of hafnium-containing fluoride - chloride fused salt mixtures is investigated from the point of view of their possible use in electrolytic preparation of hafnium and alloy as well as for obtaining the new data on determination of ion melts structure. Specific conductivity is measured in total concentration range by relative capillary method. Molar electrical conductivity and its deviation from ideality at 1200 K are computed on the basis of measured data.