A novel and effective electrochemical sensor for the determination of cefixime (CEF) in 0.04 mol L-1 universal buffer solution (pH 3.0) is introduced using gold nanoparticles electrodeposited on a multi walled modified carbon paste electrode (GNPs/MWCPE). The voltammetric behavior of cefixime on this modified electrode was studied using cyclic and square wave voltammetric techniques. The oxidation of cefixime was irreversible and exhibited diffusion controlled process depending on pH. The effect of various experimental parameters including pH, scan rate and accumulation potential and time on the voltammetric response of CEF was investigated. The results indicated that the process of oxidation of this compound is irreversible and adsorption-controlled. At the optimum conditions, the concentration of CEF was determined using square wave voltammetry (SWV) in a linear range of 1.0 x 10(-2) to 2.0 x 10(2) mu mol L-1 with a correlation coefficient of 0.9996, and the detection limit was found to be 3.0 x 10(-9) mol L-1. According to the linear relationship between the peak current and the concentration, square wave voltammetric method was successfully applied to the determination of cefixime in a pharmaceutical dosage form and a urine sample. The effects of common interferences, namely some of different cations and anions, on the current response of cefixime were investigated. This reveals that GNPs/MWCPE shows excellent analytical performance for the determination of cefixime in terms of very low detection limit, high sensitivity, very good repeatability and reproducibility over other methods reported in the literature. (C) 2013 Elsevier Ltd. All rights reserved.