Aim: Clinical monitoring of oxcarbazepine (OXC) and its metabolite licarbazepine (MHD) in biological matrix requires a sensitive and validated analytical method. The aim of this study is to develop and validate an optimized ultra performance liquid chromatography-MS/MS based bioanalytical method for the simultaneous estimation of OXC and its metabolite MHD in human plasma, using deuterated internal standard method. Materials &methods: A reverse phase ultra performance liquid chromatography analysis and mass spectrometricdetection was performed using electrospray ionization in positive ion mode as interface, multiple reaction monitoringas mode of acquisition. Results &conclusion: The linearity range was 10-4011ng/mlfor OXC and 40-16061 ng/mlfor MHD. The kinetic parameters were calculated and compared for bioequivalence. This method fulfilled the validation guidelines, could be employed for determining bioavailability and in new formulation development studies.