A poly (methyl orange) (PMO) film on the surface of carbon paste electrode (CPE) was synthesized by electrochemical process and was used for the sensitive and selective determination of L-dopa by employing voltammetric techniques. The electrocatalytic response of the synthesized film coated electrode was found to exhibit excellent activity. The simultaneous determination of L-dopa in the presence of high concentrations of Ascorbic acid (AA) and Uric acid (UA) was found to exhibit very good response at polymer film coated electrode. The effect of pH, scan rate, accumulation time and concentration of L-dopa was studied at developed polymer film modified electrode. The PMOCPE exhibited an efficient electron mediating behaviour together with well resolved peaks for L-dopa, AA, and UA in 0.1 M phosphate buffer (PBS) solution of pH 5.0. The anodic peak current showed a linear relation of L-dopa with correlation coefficient of 0.9918 and detection limit 3.7 mu M and quantification limit 12.37 mu M respectively. The results showed a good sensitivity and selectivity and high reproducibility of synthesized polymer electrode. The developed method was applied for the determination of L-dopa in pharmaceutical formulations with satisfactory results. The interfacial electron transfer behaviour of L-dopa was studied by electron impedance spectroscopy (EIS), the studies showed that the charge transfer rate was enhanced at PMOCPE when compared with bare CPE. (C) 2012 Elsevier B.V. All rights reserved.