The effects of solid-solid interactions of As2O3 and SnO doped in MnO2 were investigated. The electrical and dielectric properties of the produced composite were also studied. Pure MnO2 and doped solids having different concentrations of As2O3 and SnO were subjected to heat treatment at 700 degreesC for 24 h. The optical investigations show that As2O3 reacts with MnO2 to give mixed oxide system. The space charge polarization increases depending on SnO effect and the resulting samples demonstrate semiconductor behaviour. When the amount of As2O3 is increased, the conductivity increases proportionally. Dielectric constant was calculated to be similar to 41 at 1 MHz, and dielectric constant and loss factor are decreased at high frequencies. In dielectric relaxation, arsenic ions play an effective role and the structure illustrates dipolar relaxation behaviour. (C) 2004 Elsevier B.V. All rights reserved.