Benzotriazole (BTAH) is shown to decrease the extent of localized corrosion of alpha brass in salt water contaminated by sulfide ions. The results are interpreted in terms of competitive adsorption of BTAH and sulfide ions on the brass surface and in view of the catalytic effects of dissolved sulfide as well as sulfide scale on the rates of the partial reactions. As the concentration of BTAH increases, the degree of coverage of the surface with sulfide decreases and, hence, also the rates of the partial reactions and the overall corrosion reaction.