In this work, one dimensional gold/polyaniline (Au/PANi) nanofiber composites are successfully synthesized via electrostatic adsorption and in situ reduction of HAuCl4. By observations of field emission scanning electron microscopy (FE-SEM) and high resolution transmission electron microscopy (HR-TEM), it is clearly seen that the as-prepared Au nanoparticles were uniformly distributed on the PANi surface. In addition, the synthesized Au/PANi nanofiber composites are also characterized by X-ray diffraction (XRD) analysis, Raman, Fourier transform infrared (FTIR), and UV-vis absorption spectra, and the results further confirm Au/PANi nanofiber composites have been synthesized and the strong interaction between PANi and Au nanoparticles indeed exists. Thermogravimetry (TG) analysis indicates that the thermal stability of the nanocomposites of Au/PANi is improved compared to the pure PANi. More importantly, the nanocomposites of Au/PANi show good electrocatalytic behavior toward oxygen reduction. (C) 2011 Elsevier B.V. All rights reserved.