According to data issued by the International Agency for Research on Cancer in 2012, the estimated number of new cases of all types of cancer worldwide was estimated to exceed 10 million, and 6 million of whom receive radiotherapy. Radiotherapy is the treatment of cancer using ionizing radiation. Our study investigated the effects of x-radiation resulting from radiotherapy (RT) on the testis at the molecular level, and prospectively considered the potential protective characteristics of antioxidants against testicular damage resulting from x-radiation. Forty male Sprague Dawley rats were allocated into five groups, control (group 1), abdominopelvic region 2-Gy-ionizing radiation (group 2), whole-body 6-Gy irradiation (group 3), 2Gy abdominopelvic region irradiation and 300mg/kg NAC treatment (group 4), and 6-Gy whole-body irradiation and 300mg/kg NAC treatment (group 5). Disorganization and vacuolization were observed in the epithelial layer in atrophic seminiferous tubules in the only ionizing radiation (IR) groups. In addition, Johnsen's score decreased in the only IR groups, while testis tissue malondialdehyde (MDA) and glutathione (GSH) tissue levels increased. N-Acetylcysteine (NAC) treatment groups Johnsen's score and tissue GSH levels increased than only IR groups. On the other hand, tissue MDA levels decreased in the NAC treatment groups. The findings showed that ionizing radiation caused apoptosis in germinal epithelial cells led to the oxidative stress-mediated testicular injury. On the other hand, NAC may be useful in the prevention of testicular injury-suppressed ROS production.