Regulations for control of radioactivity in food and the environment are myriad and complex. This chapter presents a limited selection of regulations and recommendations from international agencies and some individual nations. It also presents two classes of regulations. The first class embodies recommendations issued by international organizations that, in most cases, are not legally binding and the second class of regulations represents those issued by national governments that, in most cases, have some legal status. Most guidelines specify limits on radioactivity in food and drinking water. The methodology for estimating the maximum permissible concentrations of radionuclides in food and drinking water is well established and goes back to the earliest regulations in radiation protection. Persons possessing radioactive material must obtain a license to possess and use radioactive material and to dispose of it in an acceptable manner.