This animal modelling study aimed to investigate the effects of LDR exposure on cellular ROS production, oxidative DNA damage, and alteration of cellular ultrastructure and apoptosis-related protein expressions. Ten male ICR mice were randomly divided into two groups consisting of control (Cx) and radiation (Rx) groups. On day 29 of post-acclimatisation, mice underwent total body irradiation with 100 µGy X-ray. Liver and lung tissues were assessed for the levels of cellular ROS production and Apurinic/Apyrimidinic sites generation. Ultrastructural alteration was detected using TEM, alteration of p53, Bax, and Bcl-2 expressions was determined by western blotting. Results showed that exposure to LDR significantly increased the levels of cellular ROS and AP sites in mice. Ultrastructure of the nucleus in Rx showed nuclear blebbing and structural changes in morphology that indicate cell death. Meanwhile, p53, Bax, and Bcl-2 proteins increased in expressions and altered the balance of Bax/Bcl-2 ratio. These findings may postulate that LDR exposure may enhance oxidative DNA damage and alter expression of apoptosis-related proteins.