A polyaniline coating was deposited onto an Al-2024-T3 substrate using oxalic acid as electrolyte. Both galvanostatic and potentiostatic techniques were used to deposit polyaniline on aluminum under aqueous conditions. The dc polarization studies showed that polyaniline coatings reduced the corrosion rate of Al-2024-T3 significantly by about threefold compared to that of the control. The passivation of the polyaniline-coated aluminum was characterized by reflection absorption infrared spectroscopy and cyclic voltametry.