[en] In this paper the effect of sterilization method by gamma-ray on structure and cytotoxicity of polyurethane film surface has been investigated. For this purpose reactive urethan prepolymer was synthesized by the reaction between Tdi with a mixture of Peg and castro oil (50/50, w/w). The cured prepolymer films were prepared due to the reaction of reactive prepolymer with air moister under ambient conditions. The polyurethane films were sterilized by gamma-ray (25 kGy). The surface of sterilized polyurethane film was observed by Sem and compared to that of the unsterilized film. Also, the in vitro interaction of fibroblast L 929 cells and sterilized polyurethane film was evaluated. Results showed no signs of cell toxicity