In this report are presented the preparation and the characterization of six nanocomposite membranes of formula {Nafion/[(TiO2)center dot(WO3)(0.148)](psi TiO2)} with psi(TiO2) in the range 0-2.988. These materials are based on Nafion and [(TiO2)center dot(WO3)(0.148)] nanofiller. The effect of [(TiO2)center dot(WO3)(0.148)] nanopowders on the structural, thermal, mechanical and electrical properties of {Nafion/[(TiO2)center dot(Wo(3))(0.148)](psi TiO2)} membranes was studied. The water uptake (WU) value of materials was lower than that of pristine Nafion and was correlated with psi(TiO2). The thermal transitions were investigated by modulated differential scanning calorimetry (MDSC). The mechanical parameters and relaxation processes on temperature were studied by dynamical mechanical analyses (DMA). The FT-IR ATR and mu-Raman vibrational investigations allowed to determine the structure of the hydrophobic polytetrafluoroethylene (PTFE) domains of Nafion and the interactions Nafion-[(TiO2)center dot(WO3)(0.148)] and Nafion-[H2O] in bulk materials. The analysis of complex conductivity plots were evaluated in the 10(-2) Hz-10 MHz and 5-155 degrees C regions. Results indicated that the conductivity of {Nafion/[(TiO2)center dot(WO3)(0.148)](psi TiO2)} nanocomposite membrane, with psi(TiO2) = 1.616, at 135 degrees C, is 5.0 x 10(-2) S cm(-1), while its stability range of conductivity (SRC) extends up to 135 degrees C. (C) 2009 Elsevier Ltd. All rights reserved.