Hydroxyethylmethacrylate (HEMA) is considered to be one of the important vinyl monomers. The ability of polyhydroxyethyl-methacylate (PHEMA) graft sites to consecutive chemical modification makes the use of nylon-6 fibers grafted with PHEMA a feasible bed for immobilization of a wide range of biologically active reagents, specially enzymes, drugs, cells, and immunadsorbents. Stemming from the above discussions, in this article, the graft copolymerization of HEMA onto modified nylon-6 fibers containing Polydiallyldimethylammonium chloride (PDADMAC) in the presence of Cu 2þ -K 2 S 2 O 8 as a redox initiating system was carried out, with very high rate and almost without homopolymer formation. The factors affecting the grafting reaction (monomer, K 2 S 2 O 8 and cupric ion concentrations, the amount of PDADMAC as well as the reaction temperature) were studied. Kinetic investigation revealed that the rate of grafting (R p ) of HEMA onto modified nylon-6 fibers is proportional to [HEMA] . The overall activation energy was calculated (71 KJ/mol). The fine structure, surface topography, thermal and electrical properties of parent and grafted nylon-6 fibers were investigated.