Dissolution of the anodic oxide film on antimony in sulfuric acid solution containing different concentrations of dichromate ions has been studied using impedance and potential measurements. It was found that the dissolution rate of the oxide film decreases with increasing dichromate ion concentration in the dissolution medium. The influence of Cr2O72- ions in the formation medium (H2SO4) on the properties of the anodic oxide film formed in this medium was also studied. The results reveal that the oxide film formed in the presence of high concentration of dichromate ions dissolves at a low raw which reflects its stability. This is attributed to the powerful oxidizing properties of dichromate ions which lead to the formation of an oxide film which is less susceptible to dissolution.