The present research dealt with using a carbon paste electrode (CPE) modified by gold nano-particles (AuNPs) graphene nano-sheets (GNs) and 4-hydroxy-2-(triphenylphosphonio) phenolate (HTP) in order to determine of cisplatin. The nano-composite exhibited excellent electrocatalytic activity for the determination of cisplatin by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. CV measurements were used to determine the kinetic parameters including electron transfer coefficient (α) and heterogeneous rate constant (k′) for cisplatin oxidation at the surface of modified electrode, which were 0.39 and (1.23 ± 0.17) × 10–3 cm s–1, respectively. At pH 7.0, cisplatin oxidation at the surface of modified electrode (HTP–AuNPs/GNs–CPE) was down at a potential of ~410 mV less than that of an unmodified electrode (CPE). According to DPV experiments, cisplatin oxidation ranged from 1.0 to 120.0 µM and limit of detection of 0.88 µM. The modified electrode showed acceptable function to detect cisplatin in biological samples by standard addition method.