Problems experienced with electrochemical techniques for determination of corrosion rate for steel exposed to alkaline solutions and cement mortar with and without chloride are discussed. The polarising current, used for the measurements, altered the performance of the electrodes. Therefore, different test methods gave a large divergence in linear polarisation resistance (LPR) and capacitance for the same electrodes. The methods treated are: cyclic voltammetry, potentiostatic exposure, potentiostatic pulses, galvanostatic pulses and electrochemical impedance spectroscopy (EIS). The observations support the theory first presented by Andrade et al. (Mater. Sci. Forum 192-194 (1995) 843) that redox reactions of the corrosion product tend to mask the Faraday current of the corrosive reactions of the metal.