A conducting polyaniline/diatomite composite was obtained by surface modification of diatomite using polyaniline, and was characterized by Fourier-transform infrared spectra, X-ray photoelectron spectra, conductivity and dielectric properties. Surface area, total pore volume and pore size distribution of this composite were also measured. It was found that DC conductivity of this composite decreased with the increase of temperature from 278 to 463 K. The measurements of dielectric properties showed that the polyaniline/diatomite composite had lower dielectric constant and electric loss values than that of control polyaniline in the range of measured frequency. (c) 2006 Elsevier B.V. All rights reserved.