In this study the kinetic parameters of the system Thallium(I) – 50%Methanol-Water Mixture have been determined by impedance technique using dropping mercury electrode. DC polarographic studies are basic for the plane polarographic analysis and so the system has been studied by that technique also and the transfer coefficient has been determined from this. For analysis of impedance parameters, simple Randles equivalent circuit was used. The investigation was carried out in three different supporting electrolytes, sodium perchlorate, potassium nitrate and potassium chloride and for four different concentrations of the depolariser. The double layer capacity was obtained by extrapolation method for all the systems. The reactant adsorption was not observed in sodium perchlorate and potassium nitrate but it was confirmed in potassium chloride. In the case of sodium perchlorate and potassium nitrate an intermediate nominal adsorption was observed. The standard rate constant Ksh was determined from the charge transfer resistance, which was determined from impedance plots. In all the systems, the reduction of Thallium (I) proceeds in a reversible manner and the values of Ksh were found to be less than one.