Cisplatin [cis-diamminedichloroplatinum (II)] is an effective anti-neoplastic agent that has been used to treat various types of solid tumor. However, it is known to cause several side effects, thereby cisplatin therapy is particularly restricted to severe nephrotoxicity. To monitor the efficacy and safety of drug treatment, it is important to determine the concentration(s) of the active species in target tissues. Capillary electrophoresis (CE) allows the separation of a wide range of compounds with a unique combination of high efficiency, short analysis time, low cost with little sample and background electrolyte (BGE) consumption, making it an economical and eco-friendly approach. To achieve these goals, Micellar electrokinetic capillary chromatography (MEKC) was found to be the most suitable capillary electrophoresis mode. Therefore the aim of this work is to develop and validate a CE method to determine cisplatin concentration in tumor tissue. The optimized BGE composed of a mixture of 65 mM NaH2PO4, 40 mM Na2B4O7 and 90 mM SDS at pH 8.5. Elution of cisplatin was obtained within 12 min with good linearity (R2 = 0.9997, 0.9991) for concentrations of 20 to 320 mg.L-1 and 25 to 300 mg.L-1 for cisplatin in water and matrix respectively. The LOD values were 5.7 and 7.2 mg.L-1 for cisplatin in water and tumor tissue (biological matrix), respectively and the LOQ values were 19 and 24 mg.L-1 for cisplatin in water and in tumor tissue (biological matrix), respectively.