Medical devices made of polycarbonates are generally sterilized by ionizing radiation. The effect of irradiation on the response of polycarbonate to various components of body fluids was studied in this work, Polycarbonate films prepared by solvent casting technique from various solvents were gamma-irradiated in the range of 0-200 kGy. Characterizations of the films were achieved by contact angle and water-uptake studies as well as atomic force microscope (AFM) images. It was found that gamma-irradiated films were more hydrophilic than unmodified films, AFM images showed that surface roughness increased with gamma irradiation, Protein adsorption experiments conducted with human plasma demonstrated that protein adsorptions drastically increased by increasing the applied irradiation dose. The unirradiated and gamma-irradiated films were contacted with human blood in in vitro systems. Loss of the blood cells and clotting times were followed. Loss of blood cells in the plasma contacting with gamma-irradiated films was negligible. Any significant change was also followed for clotting times with gamma-radiation dose.