MnO2 oxide systems containing different weight percent of TiO2 and As2O3 were prepared. A number of studies, i.e., Fourier Transform Infrared, X-ray powder diffraction, electrical conductivity and dielectric properties on these mixed oxide systems, were carried out. These investigations show that the doping amount of As2O3 and TiO2 influences structure, conductance, electrical and dielectric behavior of MnO2 system. The optical investigations show that MnO2 reacts with As2O3 to form Mn2As2O7 and Mn2O3. TiO2 appears in the form of rutile phase. Dielectric constants epsilon' and epsilon '' of 5 wt.% As2O3-doped composite were calculated to be similar to 30 and similar to 38 at 13.5 kHz, respectively. The formation of Mn2As2O7, Mn2O3 and the presence of TiO2 rutile phase and the degree of polarization or charge displacement depending on frequency played an effective role in the magnitude of epsilon', epsilon '' and sigma. (C) 2004 Elsevier B.V All rights reserved.