The electrochemical behaviour of cytochrome c was studied on gold and glassy carbon electrodes as a function of pH, the type of anions present in the electrolytes and temperature. It was established that the stability and the reversibility of electron transfer processes are determined by the adsorption of the protein on the electrode surface, which can be greatly influenced by factors having an effect on the double layer around the molecules. Stable electrochemistry can be observed if the conditions are suitable for the native, monomeric form of cytochrome c to be preserved on the surfaces.