The kinetics of the electropolymerization of 2-mercaptobenzimidazole (2-MBI) on a brass substrate in alkaline solution containing methanol was investigated using cyclic polarization, chronoamperometry and electrochemical impedance techniques. The polymeric film was prepared by successive cycles of potential of a Cu-Zn electrode between 0.2 and 2.4 V. During the second cycle, the oxidation peak of the monomer disappears indicating the formation of the insulating film. We have also shown that the monomer oxidation reaction is essentially irreversible and controlled by a diffusion process. The protective effect of the film formed on brass has been studied in a 3% NaCl solution. The results showed an important inhibition efficiency, about 96% for 4 h of testing time. (C) 2000 Elsevier Science Ltd. All rights reserved.