There are two known tungstates - In6WO12 and In-2(WO4)(3) - in the In2O3-WO3 system. Transport properties of ceramics samples of both tungstates were investigated using impedance spectroscopy as a function of temperature and oxygen activity, the EMF-technique, and Tubandt-type experiments in cells with Pt and WO3-electrodes. Conduction in In-2(WO4)(3) was shown to be primarily ionic, but no evidence of In3+ conduction was observed. In6WO12 is n-type semiconductor with relatively low conductivity. (C) 2007 Elsevier B.V. All rights reserved.