Magnesium oxide (MgO, pure) and zinc added MgO nanoparticles were synthesised by a simple microwave assisted solvothermal method. The concentrations of impurity used in the present work were 0.25 M and 0.50 M. All samples were annealed at 400°C for 1 h to improve the ordering. The prepared pure and zinc added magnesium oxide nanoparticles were characterised by powder X-ray diffraction (PXRD), energy dispersive spectroscopy (EDS) and scanning electron microscopy (SEM). PXRD studies of pure and zinc added MgO nanoparticles showed that all samples belong to crystalline nature with cubic structure. The grain size of all samples were determined from the XRD results and it belongs to nanometre scale. The EDS confirmed the presence of zinc, magnesium and oxide elements in the respective prepared samples. The scanning electron microscope images confirmed that the prepared samples possess nanometre dimensions. The electrical properties such as AC conductivity, dielectric constant and dielectric loss were measured at different temperatures in the different frequency range by involving the impedance analyser of all the prepared samples.