Combination of pressure and electrically driven membrane processes in one device is an intriguing but scarcely investigated option. We report here such a hybrid electro-baromembrane process applied to separate monovalent cations. In this process, an electric field and a pressure field are simultaneously applied to a track-etched membrane with an effective pore diameter of 28 nm in a way that the electric force and pressure force act on competing ions in opposite directions. The cases of separation of K+ and rhodamine cation and K+ and Li+ are studied experimentally. The permselectivity coefficient for separation of K+/Rh6G+ and K+/Li+ was found equal to 220 and 36, respectively; the K+ flux density in the first and second cases was 7.2 and 4.0 mol/(m2h), respectively. These results were obtained with rather low driving forces, the voltage and pressure drop across the membrane were 1 V and 0.12 bar, and 0.5 V and 0.28 bar in the first and second cases, respectively. The method allows the separation of ions with the same charge when consuming low energy, which is almost impossible using other membrane methods. A simplified mathematical model, which roughly describes the experimental data, is developed.