Radiation protection is one of the most important issues in nuclear medicine, related to all diagnostic and therapeutic procedures, with respect to the safety of the patient, involved staff and environment. This chapter is focused on the basic requirements in the daily medical practice with ionizing radiation; it describes the effective dose limits for the occupational persons and for the general public. Presented here are the general rules to reduce patient’s irradiation; the physical factors with impact in radiation protection; the special recommendation for breastfeeding and childbearing female patients, also the procedures in case of minor or major nuclear events.