This study was conducted to investigate the application of gamma irradiation as a means to control the release rate of catechin from polymer matrix. First, chitosan and polyvinyl alcohol (1:3) were mixed and later chitosan nanoparticles containing catechin were added to the mixture and coated on polylactic acid surface and then films were irradiated at 0, 40 and 60 kGy doses of gamma-ray. Irradiation lowered the water solubility value of the films, furthermore 60 kGy dose reduced the water vapor permeability and tensile strength without significant effect on elongation at break of films. Results of release test indicated that gamma-ray decreased release rate of catechin from polymer matrix and generally release in high-fat simulant was about 2.5 times slower than low-fat simulant. This study was undertaken to design a packaging material with controlled release ability of antioxidant compound over time for further application in oxidation-sensitive foods.