The pitting corrosion, passive film morphology, and surface composition of copper were studied in chloride-containing bicarbonate buffer solutions using multielectrode arrays and single electrodes. Cu was shown to be susceptible to pitting in 0.01 and 0.1 M Cl¯, but to experience active dissolution in 1 M Cl¯. The passive film morphology and composition were investigated using the single-electrode setup. Surface analyses showed the presence of pits in both 0.01 and 0.1 M Cl¯ buffer solutions. The results indicated the dependency of passive film morphology and composition on both charge density and applied potential.