This study concerns the investigation of the effect of reaction conditions on the radiation-induced grafting of styrene into poly(ethylene-alt-tetrafluoroethylene) base film. Grafting was obtained by the pre-irradiation method, using styrene in isopropanol/water mixture. The influence of irradiation and reaction conditions, such as irradiation dose, monomer concentration, water content of the grafting solution and reaction temperature on the grafting yield was investigated. The grafting kinetics in terms of initial polymerization rate (r p0 ), radical recombination rate (c) and delay time (t 0 ) was evaluated. It was found that the rate and the extent of grafting were strongly dependent on the grafting conditions. The order of dependence of the rate of grafting was found to be 0.46, 1.5 and 0.62 for pre-irradiation dose, monomer concentration and water content in the grafting mixture, respectively. The activation energy was determined to be 98.4 kJ/mol for the temperature range of 50-80 °C. The use of kinetic equations for the polymerization gives a useful description of the grafting process. It was determined that the initial polymerization rate and the radical recombination rate vary significantly with reaction conditions. The delay time is dependent mainly on irradiation dose and to some extent on monomer concentration.