Acute and chronic toxicity tests with sodium iodate were carried out on mice and rabbits to determine the feasibility of using sodium iodate in the place of iodide for the iodization of salt. It was found that mice tolerated single oral doses of 250 mg of sodium iodate per kg of body-weight, while rabbits tolerated twice-weekly oral doses of 10 mg per kg of body-weight for six weeks. Long-term oral administration of sodium iodate to rabbits and their offspring at a level of 1 mg per kg of body-weight twice weekly, for periods of up to one year, produced no signs of ill-health. Histological examination showed that the livers, kidneys, and retinae of these rabbits were normal. The equivalent weekly amount for a man weighing 70 kg would be 140 mg. It is therefore concluded that it would be safe to recommend the iodization of salt with sodium iodate to a level of 1 part of NaIO(3) in 20,000 parts of salt. On the basis of a weekly intake of 70 g of salt, this would provide 3.5 mg of NaIO(3), which is equivalent to 2.2 mg of iodine. Finally, the author considers that sodium iodate should be used for the iodization of salt only when the type of salt available or the environmental conditions cause excessive loss of iodine from iodide.