Polyaniline/TiO2-SiO2 composites were prepared by an in situ chemical oxidation polymerization approach in the presence of hybrid TiO2-SiO2 fillers. The obtained polyaniline/TiO2-SiO2 composites were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectrometer (FTIR), X-ray diffraction (XRD), thermogravimetry (TG), and current-voltage (I-V) measurements. SEM picture shows a variation in morphology of polyaniline (PANI) from fiber shape to relatively regular particle shape with increasing TiO2-SiO2 contents in the composites. The floccule-like structures were observed by high resolution TEM, which may help improve the efficiency of conductive network. SEM, XRD, TG, and FTIR spectra all reveal that a relatively strong interaction exist between TiO2-SiO2 and PANI. The I-V characteristics in such composites indicate that the charge transport is mainly governed by the space charge effects, which occurs at the interface between the conducting PANI and TiO2-SiO2. Meanwhile, PANI/TiO2-SiO2 composites exhibit significant increase in conductivity than PANI/TiO2 or PANI/SiO2. The reasons about high conductivity of PANI/TiO2-SiO2 have also been discussed. (c) 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2288-2295, 2013