The benefits and concerns about treating foods with ionizing radiation are reviewed. Radioactivity cannot be induced in foods by treatment with gamma rays from 137Cs or 60Co, X-ray sources of 5 MeV or lower energy, or electrons of 10 MeV or lower energy. The evidence supports the safety and efficacy of using ionizing radiation for insect disinfestation of grains; dried spices, vegetables and fruits; and fresh fruit. Species and dose dependent phytotoxic and vitamin changes may occur in some fruits at greater doses than currently approved by the U.S. Food and Drug Administration. Irradiation can inactivate protozoan or helminth parasites and significantly decrease the probability of viable food-borne bacterial pathogens in fish, poultry, and red meats. The titers of amino acids, fatty acids, and vitamins of chicken meat sterilized by thermal, electron-beam, or gamma radiation are presented. On the whole, the data support the safety and efficacy of the process.