In 2001, Dietary Reference Intakes (DRIs) for iodine were set for the different gender and life-stage groups by the Institute of Medicine. Because of the serious consequences of iodine deficiency for the developing fetus and infant, there is particular interest in further understanding optimal iodine nutrition and improving the monitoring of iodine status, particularly during infancy, pregnancy, and lactation. This review discusses the basis for the current DRIs for iodine and the evidence that may be needed for considering and conducting the reevaluation of one or more of the DRIs.