The radiation-induced graft copolymerization of 2-hydroxyethyl methacrylate (HEMA) onto poly(gamma-methyl-L-glutamate)membranes was investigated in ethanol. The effects of dose, dose rate, concentration of HEMA, and temperature on the degree of grafting were studied. The initial rate of grafting copolymerization shows the following functional relationship equation : dG(0)/dt = k[M](0)(D) over dot(0.56). The average values of the apparent constants at 27 and 37 degrees C for the initial rates of grafting are k(1) = 51 and k(2) = 91 G%h(-0.44) kGy(-0.56) mol(-1) L, respectively. The apparent activation energy of grafting copolymerization is E = 10.7 kcal/mol.