Impedance measurements have been made in the frequency range 10 Hz-50 kHz and temperature range from 25 to 55 1C on poly(ethylene oxide) doped with iodine. The iodine concentration ranged from 0% up to 10% by weight. Impedance, dielectric constant, dielectric loss, AC conductivity and activation energy showed frequency and temperature dependence. It was found that impedance decreases with increasing frequency and temperature as well. The values of dielectric constant and dielectric loss decrease with increasing frequency, but increase with increasing temperature. For doped PEO composite films, the values of dielectric constant and dielectric loss vary anomalously in the low doping level of iodine. In addition, it was found that the AC conductivity of PEO composite films increases on increasing the frequency or the temperature. In general, the observed dependence of the dielectric constant, the electrical conductivity, the relaxation time and the thermal activation energy on the measuring conditions is attributed to the formation of molecular and charge-transfer complexes. This is in addition to other factors such as polarization and the electron hopping process.