The electrochemical oxidation of 2-mercaptoethanol has been examined on cobalt phthalocyanine (CoPc) + poly(2-chloroaniline) (PANCl) modified electrodes. A simple and reproducible procedure is described to obtain the modified-polymer electrodes, PANCl electrodes are modified by dispersing three different percentages of CoPc (0.1, 1 and 20%). These modified electrodes show electrocatalytic activity for 2-mercaptoethanol electro-oxidation in an acid medium. The evaluation of the electrocatalytical response of PANCl + CoPc films suggests that the diffusion rate of electroactive species into the film is improved when the polymer reaches the oxidized state.