A novel, low-cost and sensitive electrochemical detectionmethodwas proposed for quantitativemeasurement of tramadol (TRA) based on using a pencil graphite electrode (PGE) modified with multiwalled carbon nanotubes (MWCNTs) and gold nanoparticles (AuNPs). The electroanalysis of tramadol was carried out by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. Field emission scanning electron microscopy (FE-SEM) was used to investigate the surfacemorphology of the modified electrode and the electrochemical properties of f-MWCNTs/AuNPs/ PGE surface were evaluated using electrochemical impedance spectroscopy (EIS) technique. The effect of several significant parameters such as pH, scan rate and immersion time of PGE in f-MWCNTs suspension was examined and they were optimized. The influence of interfering species including ascorbic acid, uric acid and citric acid was evaluated and the obtained results showed that the developed sensor has a high selectivity for tramadol molecules. A linear relationship was observed between differential pulse voltammetry response of themodified electrode and the concentration of TRA in the range of 12–100 and 100–3000 nM. The proposed electrode showed high sensitivity and selectivity for determination the concentration of tramadol in tablet and biological fluids

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