A square-wave voltammetric procedure for electroanalytical determination of Losartan (LOS) in its tablets, human urine and blood serum in Britton-Robinson buffer (pH 3.0, 0.1 mol L^–1) as a supporting electrolyte were studied. The electrochemical stripping procedure for trace measurement of LOS was developed based on the adsorption of Cu (II)- LOS complex on a hanging mercury drop electrode and applied to quantification of the drug . Cyclic voltammetry was used to characterize the interfacial and redox behavior of the adsorbed Cu (II)- LOS complex. The solution conditions and instrumental parameters for quantitative determination were optimized and a linear variation ranging from 5×10^-10 mol L^-1 to 5×10^-7 mol L^-1 with detection limit (LOD) 1.87×10^-10 mol.L^-1 in presence of 5×10^-7 mol.L^-1 of Cu (II) ions for quantification of LOS. The sharp peak of the adsorbed Cu (II) - LOS complex associated with an effective interfacial accumulation of the drug with good recoveries. The observed data had been subjected to statistical analysis, which revealed high reliability and precision. The degree of interference from potentially present metal ions and organic compounds on (SWAdCSV) signal for Cu ( II) - LOS complex was evaluated. The intra-day relative standard deviation (RSDs) ranged from 0.331 to 0.418% at three different concentrations and inter-day RSDs ranged from 0.055 to 0.271%. The procedure was successfully applied to the quantification of the drug in human urine and serum samples. The mean percentage recoveries were 99.6 ± 0.15 and 98.0 ± 0.256, respectively. The determination of the LOS in its tablets was achieved using the standard addition method.