In this study, the nano-sepiolite modified carbon paste electrode (CCPE) was prepared for the determination of ketoconazole (KC). The effects of pH, the proportion of the electrode modifier, deposition potential, and deposition time were investigated. Ketoconazole shows one irreversible oxidation peak at about the potential value of 0.6-0.7 V at different pH values. CV studies show that the modified electrode performed a catalytic effect on the peak signal of KC compared to the bare electrode. This catalytic behavior of CCPE was used for the development of a sensitive detection method. The impact of pH and scan rates on the anodic peak potentials and currents were examined, and the scan rate results show that the oxidation behavior of KC was controlled by the adsorption process at the CCPE surface. Therefore, adsorptive stripping differential pulse voltammetry (AdsDPV) and adsorptive stripping square wave voltammetry (AdsSWV) methods were developed for KC analysis. The two different linear ranges were obtained as (0.1-1.0) nM and (3.0-10.0) nM for AdsDPV, and (0.1-10.0) nM and (3.0-10.0) nM for AdsSWV, respectively. The detection (LOD) and quantification (LOQ) limits were found to be 0.017 nM and 0.056 nM for AdsDPV and 0.025 nM and 0.083 nM for AdsSWV, respectively. Besides, the proposed new sensor has obtained very high recovery values in the analysis of KC in the pharmaceutical shampoo.