In the present study, Nafion/Titanium Silicon Oxide (TiSiO4) nanocomposite membranes were prepared by recasting method for proton exchange membrane fuel cells. The composite membrane containing 10wt% TiSiO4 had a membrane thickness of 80 mu m. The membrane was characterized by thermogravimetric analysis, X-ray diffraction (XRD), and scanning electron microscopy (SEM). SEM and XRD results have proven the uniform and homogeneous distribution of TiSiO4 in Nafion, and consequently, the crystalline character of these membranes was enhanced. The energy-dispersive X-ray analysis has also indicated uniform distribution of TiSiO4 on the surface of the nanocomposite membrane. The existence of nanometer-size TiSiO4 has improved the thermal resistance, water uptake, and proton conductivity of composite membranes. Single fuel cell tests were performed at different operating temperatures with membrane electrode assemblies prepared by Nafion and Nafion/TiSiO4 nanocomposite membranes. The highest performance was obtained with Nafion/TiSiO4 membrane at 85 degrees C. These results indicate that Nafion/TiSiO4 composite is a promising membrane material for possible use in proton exchange membrane fuel cells. Copyright (c) 2012 John Wiley & Sons, Ltd.