The main purpose of this paper is the electrochemical oxidation of azo linkage –N=N– and to obtain some data regarding the electrochemical behavior of Methyl Orange on different electrodes and conditions (pH, electrolytes, concentrations). Different electrode materials, like CV (glassy carbon), Hg and BDD (boron doped diamond) were used to investigate the electrochemical behavior of the mono-azo dye, especially of a model molecule methyl orange, but also for other substituted azo dyes. The results obtained from the voltamograms are useful to establish the influence of the factors mentioned earlier, on the discoloration yield.