Quantitative evaluation of 5-Hydroxy-L-tryptophan (5-HTP) in seed powder of Griffonia simplicifolia (pharmaceutical tablet source) using gold modified pencil graphite electrode (GPGE) was carried out by differential pulse voltammetric technique (DPV) and amperometry. The percentage of 5-HTP detected by DPV and amperometry is concurrent with that of Uv-Vis spectroscopic results. GPGE shows high electro-catalytic activity and excellent analytical performance towards the oxidation of 5-HTP.