Gamma ray radiation-induced grafting was carried out on regenerated cellulose hollow-fiber membranes as the substrate polymer and empolying a number of monomer and solvent systems. The monomers used include styrene, maleic acid, acrylonitrile, acrylamide, and acrylic acid. Characterization of the graft copolymers was done by measuring their tensile properties in terms of breaking loads and breaking extensions. Permeating properties of the modified membranes were also assessed by measuring the water flux of each membrane. Membranes grafted with styrene showed improved tensile and permeation properties, while co-irradiation graftings using acrylamide and acrylic acid as monomer only showed improved tensile properties but not the permeation properties of virgin membranes. For a given monomer, the pre-irradiation grafting technique generally produced membranes with lower water fluxes than those produced using co-irradiation grafting.