Graphite oxide (GO)/Nafion composite membranes were prepared and used for polymer electrolyte membrane fuel cells (PEMFCs). Membranes were characterized by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) which showed the distribution of graphite oxide sheets in a Nafion polymer matrix. Fourier transform infrared spectroscopy data (FTIR) for Nafion and GO showed vibrations at 3440 cm⁻¹ which was attributed to intermolecular hydrogen bonding and at 1724 cm⁻¹ ascribed to the CO stretching frequency. The proton conductivities of GO (4 wt%)/Nafion composite, Nafion 212 and Nafion recast membranes at 30 °C and 100% humidity were 0.078, 0.068 and 0.043 S cm⁻¹ respectively. The fuel cell performance of the GO (4 wt%)/Nafion composite membrane gave a maximum power density of 415 mW cm⁻² at 0.390 V at 60 °C. At 100 °C a GO (4 wt%)/Nafion membrane fuel cell performance of 212 mW cm⁻² was obtained which was much better than those of Nafion recast and Nafion 212 under 25% relative humidity.