Human beings are exposed to ionizing radiations everyday. Therefore, the development of radioprotectors has become very important as radioprotectants can prevent humans from the deleterious effects of radiation. This book thus, focuses on the radioprotective nature of some commonly found antioxidants. Some antioxidants and phytochemicals are protective against ionizing radiations when administered at pharmacological doses. When administered after irradiation, naturally occurring antioxidants may also provide some protection against low-dose or low-dose-rate irradiation.