To improve the performance of Nylon 4 membranes, this study attempts to utilize 60Co γ-ray irradiation which induces vinyl monomers to be grafted onto Nylon 4 membranes for desalination purposes. Sodium styrene sulfonate, acrylamide, vinylacetate, and styrene are the grafting monomers. The transport properties and mechanical strength of the γ-ray irradiation-grafted Nylon 4 membranes are studied. Both the water flux and salt rejection of sodium styrene sulfonate-grafted membranes increase significantly, compared to Huang's results. The other grafted membranes also show increased salt rejection.