The performance of the nanofiltration process was investigated for uranium separation from binary aqueous solutions of UO22+-K+ and UO22+-Ca2+ containing uranium in high concentration ranges. Rejection coefficient, permeate flux, and membrane selectivity of PES-2, NF-1, and NF-2 membranes under various operational conditions of pH, pressure, and concentration of interfering cation were evaluated. In most cases, the order of metal rejections with these membranes was UO22+ > Ca2+ > K+. According to the obtained results, the nanofiltration process could be effectively used for selective uranium separation from aqueous solutions containing uranium and other monovalent and divalent cations.