The 24-hour radioactive iodine uptake remains a very useful clinical tool for evaluating the thyroid gland; however, the normal values have changed over the years. The traditional values of 15% to 45% are clearly not applicable today and the revised values of 9% to 32% are suspect in some areas where iodine content is rapidly changing in the general diet. The values in a relatively stable population in Ft. Smith, Arkansas, without significant access to a continuous-batch bread with a high iodine content do confirm the national trend of the early 1970s suggesting an overall normal range from 11% to 30%. Values in men were found to be lower with a range from 11% to 23%, whereas in women the values ranged from 13% to 32%. Each nuclear medicine department should be responsible for establishing its own normal range and reevaluating it on a fairly routine basis—certainly whenever known dietary iodine factors change.