The embeddable MnO2-electrode for use in concrete has been tested and used in the field since 1986. The present paper supplements earlier publications and presents new data on short and long term stability, polarisation behaviour, temperature response and performance behaviour in concrete with cathodically protected steel subjected to climatic cycling and field experience. Results compare favourably with published data for other embeddable electrodes and show that the MnO2-electrode has found wide acceptance, mainly because of its very good long term stability.