Results found on stability of Prussian Blue (PB) films deposited on ITO electrodes show that these films can withstand more than 10(5) cycles around the reduction system [Prussian Blue <-> Prussian White (PW)]. The greater quantity of water molecules inside the water-stored films avoid its solubilization during the oxidation process, although stability is slightly decreased when cycled around the reduction system (PB <-> PW) only. K+ inserted into the film suffers a recorganization process during cycling around the whole voltammogram and allows the total oxidation to Prussian Yellow (PY) and the successive cycling around the oxidation system (PB <-> PY). The presence of Fe(CN)(6)(4-) in the medium can avoid the solubilization process during the oxidation of PB to PY. However, the film loses its adherence.