The electrochemical behavior of some rhodanine sulfa drug azo compounds in Britton-Robinson universal buffers containing 40 % (v/v) ethanol was investigated at the mercury electrode using dc-polarography, cyclic voltammetry and controlled potential coulometry. The examined azo compounds were reduced in all pH in two diffusion-controlled irreversible steps, the first step corresponding to the cleavage of the N=N center via the consumption of four electrons whereas the second one is due to the saturation of the S=C of the rhodanine ring. The mechanistic path way of the electrode reaction of the studied compounds was elucidated and the kinetic parameters were calculated and discussed. The dissociation constants (pKa) values of the examined azo compounds and the thermodynamic parameters were determined potentiometrically.