A self-humidifying composite membrane based on Nafion (R) hybrid with SiO2 supported sulfated zirconia particles (SiO2-SZ) was fabricated and investigated for fuel cell applications. The bi-functional SiO2-SZ particles, possessing hygroscopic property and high proton conductivity, were homemade and as the additive incorporated into our composite membrane. X-ray diffraction (XRD) and Fourier infrared spectrum (FT-IR) techniques were employed to characterize the structure of SiO2-SZ particles. Scanning electronic microscopy (SEM) and energy dispersive spectroscopy (EDS) measurements were conducted to study the morphology of composite membrane. To verify the advantages of Nafion (R)/SiO2-SZ composite membrane, the IEC value, water uptake, proton conductivity, single cell performance and areal resistance were compared with Nafion (R)/SiO2 membrane and recast Nafion (R) membrane. The single cell employing our Nafion (R)/SiO2-SZ membrane exhibited the highest peak power density of 0.98 Wcm(-2) under dry operation condition in comparison with 0.74 Wcm(-2) of Nafion (R)/SiO2 membrane and 0.64 Wcm(-2) of recast Nafion (R) membrane, respectively. The improved performance was attributed to the introduction of SiO2-SZ particles, whose high proton conductivity and good water adsorbing/retaining function under dry operation condition, could facilitate proton transfer and water balance in the membrane. Crown Copyright (C) 2008 Published by Elsevier B.V. All rights reserved.