RE tungstates Ln14W4O33 ( Ln = Nd, Sm, Gd) with a pseudorhombohedral structure were synthesized in the Ln2O3-WO3 systems, using the method of mechanical activation and subsequent high-temperature annealing at 1450-1600 degrees C for 4h. It was found that these compounds have oxygen-ion conductivity. Nd14W4O33 demonstrates the maximum of oxygen-ion conductivity (4 x 10(-4) S / cm at 700 degrees C). The dependence of the total conductivity on the oxygen partial pressure was investigated for Sm14W4O33. It was shown the range of pure oxygen-ion conductivity at 700 degrees. is 10(-17) - 0.21 atm. The conductivity of the samples decreases after prolonged their exposure in water at room temperature due to the diffusion of Ln cations into water.