While benzotriazole (BTAH) is an excellent inhibitor for the corrosion of copper in unpolluted media, it promotes corrosion in sulfide-polluted salt water. BTAH looses its remarkable inhibiting efficiency in the unpolluted medium and allows corrosion rates that are greater than those in the absence of BTAH. Scanning electron microscopy images revealed extensive general corrosion. On the other hand BTAH inhibited the anodic dissolution of copper at more noble potentials in the polluted medium. The results are discussed in terms of competition between the sulfide ions and BTAH for adsorption on the surface and for complex formation with copper ions. (c) 2006 The Electrochemical Society.