The electrochemical response of chalcopyrite was studied using electrochemical noise analysis (ENA). The assay was carried out under constant aeration using 30 mL in two electrochemical cells containing iron-free mineral salts solution. These cells were initially monitored for 56 hours. After 72 hours, 7.25×1010 cells mL-1 of A. ferrooxidans strain LR were added in both cells and monitored until 128 h. Subsequent to this period, 0.927 mmol L-1 of silver ions and 400 mmol L-1 of chloride ions were added each one separately. Both conditions were monitored until 168 hours. According to results obtained, it was observed that Cl- ions addition induced an accelerated corrosion process. However, there is a tendency of the system to reach the stationary state due to repassivation of the electrodic surface. In the other side, the Ag+ addition contributed for the maintenance of the oxidant atmosphere, in spite of controversial effect caused by considerable variations in the Rn values, resulting in a instability in the chalcopyrite reactivity.