In this study, 2-hydroxy ethyl methacrylate (HEMA) monomer was grafted onto poly(ethylene terephthalate) (PET) films using benzoylperoxide (BP) initiator. PET films were pretreated in dimethyl sulfoxide (DMSO) for 1 hour at 140degreesC before the polymerization process was carried out. The change of grafting yield with polymerization time, temperature, initiator, and monomer concentrations were investigated. The optimum polymerization temperature, time, initiator, and monomer concentrations were found to be 85degreesC, 4 hours, 0.5 M and 2.2 x 10(-2) M, respectively. The effects of initiator and monomer diffusion times onto grafting were also investigated, and found to cause an increase in the grafting yield. Kinetic parameters and the activation energy for the grafting were calculated. Water absorption capacity and intrinsic viscosity of the grafted films were determined. Further, the grafted films were subjected to FTIR spectroscopy, scanning electron microscopy (SEM), and mechanical tests.