The transient currents and the voltage holding ratio (VHR) generated by an applied direct voltage have been measured in nematic liquid crystal (LC) cells. The experimental results show that doping insulating nanoparticles such as ZnO, TiO(2) and Si(3)N(4) in nematic LCs leads to a reduction of the moving-ion density in cells and thus drastically reduces the transient currents and threshold voltage. This doping method improves the electro-optical characteristics in nematic LC cells. Moreover, we find that the VHR values are maintained higher than 95% in these doped LC cells. Such a high VHR observed in doped LC cells is a superior feature for future LC display applications.