[en] Monte Carlo method has been applied extensively in radiation transport studies. It can also be of great help for designing or upgrading a ⁶⁰Co γ-ray irradiator by providing theoretical estimations of dosimetry distribution in the product containers and radiation protection effects of the shielding. In this paper, Monte Carlo simulations were performed using PENELOPE transport code for dosimetry distribution in product containers of a new ⁶⁰Co γ-ray irradiator, which has a 228 cm (w) x 200 cm (h) source plaque with 24 source pencils (12.5 kCi/pencil) and 36 irradiation positions in six paths for over head carriers of 75 cm (l) x 62 cm (w) x 190 cm (h). A carrier that has completed the first three paths is turned 180 degree to ensure uniform irradiation of the two sides. Fig.1 is dosimetry simulation results with empty carriers (with air), while Fig.2 is the results with carriers loaded with products in average density of 1 g/cm³ (with water). A carrier was divided into 120 voxels for the MC simulation, and dosimetry uniformity of the carrier is 1.28 . (authors)