Electrochemical behavior and adsorption-diffusion properties of lercanidipine (LCN) on a glassy carbon electrode (GCE) were investigated in a mixture of ethanol-Britton Robinson buffer (BR) using voltammetric methods. From experimental results LCN was found to be reduced irreversibly via a single four-electron process controlled mainly by diffusion with some adsorption contribution at about -0.65 V (vs. Ag/AgCl reference electrode). Therefore, a new, accurate, rapid, selective and simple square-wave cathodic adsorptive stripping voltammetric (SWCAdSV) method could be developed for direct determination of LCN in pharmaceutical preparations, spiked human urine and spiked human serum samples without time-consuming steps prior to drug assay. The peak current of the reduction wave linearly changed with the concentration of LCN in the concentration range between 4.0 x 10(-8) molL(-1) and 7.6 x 10(-6) molL(-1) in two different regions where optimum preconcentration potential and optimum preconcentration time were applied as -0.20 V and 90 s, respectively. The limit of detection (LOD) and the limit of quantitation (LOQ) values were found to be 2 x 10(-8) molL(-1) (0.01 mgL(-1)) and 6 x 10(-8) molL(-1) (0.04 mgL(-1)), respectively. The method was applied to determine the content of LCN in commercial pharmaceutical preparation, spiked human serum and spiked human urine. The method was found to be highly accurate and precise, having a relative standard deviation of less than 10% in all applications.