Nd5.5WO11.25-δ, (Nd5/6La1/6)5.5WO11.25-δ and Nd5.5W0.5Mo0.5O11.25-δ mixed oxides have been prepared using mechanochemical activation (MA) of Nd2O3-WO3, Nd2O3-La2O3-WO3, Nd2O3-MoO3-WO3 mixtures in a high-power planetary ball mill. Genesis of these tungstates structural properties was studied by XRD, SEM, TEM with EDX analysis, 1H NMR, IR and Raman spectroscopy. X-ray diffraction has revealed that MA results in formation of a pure fluorite structure already after milling. High-density ceramic pellets have been obtained after sintering at 1350 °C. Transport properties of Nd5.5WO11.25-δ mixed oxide were improved by the partial substitution of Nd with La in (Nd5/6La1/6)5.5WO11.25-δ and W with Mo in Nd5.5W0.5Mo0.5O11.25-δ samples. For all samples the electrical conductivity values measured in a humid atmosphere (up to ~ 10−3 S/cm at 550 °C) exceed those measured in a dry atmosphere indicating the proton character of conductivity.