The electrode resistance (Re1) at low over-voltages has been determined for Bi2O3 free and Bi2O3 doped yttria-stabilized zirconia with sputtered platinum electrodes. The anode and cathode resistances are measured separately and are equal. Bi2O3 causes a decrease of the electrode resistance at small overvoltage and with 5×10−4<PO2 ≤, 1 atm. The rate determining step for the electrode reaction under the measuring conditions probably is a charge-transfer process in which oxygen adsorbs dissociatively on the bismuth free and associatively on the bismuth doped samples. The complex impedance behaviour of the electrode reaction can be interpreted in terms of R-C circuits in the PO2 range of 10−2−1 atm.