Polymerization of aniline and pyrrole in the presence of copper(II) coming from different salts were studied by cyclic voltammetry. The systems used are: polymer/CuCl2/HCl, polymer/CuSO4/H2SO4 and polymer/Cu(NO3)2/HNO3 ). The polymer/metal mol ratios were 10/1 in both cases. The voltammograms were recorded at pH = 0 under constant potentiodynamic regime of 100 mV. s-1. It was found that aniline polymerizes in presence of Cu(II) and of all the strong acids tested (HCl, H2SO4 and HNO3). The best medium to obtain polyaniline was Cu(II) in 1 M HCI. Both polyaniline and poly(pyrrole) showed a better voltammetric behavior in HCl medium. It was attributed to the CuCl2- or CuCl3(2-) complex formation which can be incorporated to the polymer when it is electro-oxidized. It was not possible polymerize pyrrole in H2SO4.