Gamma-ray irradiation process is very useful to modify the surface of the polymericsubstrates. In this study, we prepared gamma-ray irradiated synthetic biodegradable polymerfilms, and investigated the deposition behaviors of calcium phosphate on them by immersingsimulated body fluids (SBF). The calcium phosphate was successfully coated on the PLGA filmsafter immersing in the 5× SBF. The amounts of deposited calcium phosphate on the film increasedas gamma-ray irradiation doses and immersing time increased, in which nuclear formation ofcalcium phosphate on the films may be affected or accelerated by radiation exposure. Therefore,gamma-ray irradiation dependent surface modification can be useful in bone tissue engineering.