Iodine is a trace element in the human body, its only known function is the synthesis of thyroid hormones. Effects of iodine deficiency, termed iodine deficiency disorders (IDD), include endemic goiter, hypothyroidism, cretinism, decreased fertility rate, increased infant mortality and mental retardation. 2.2 billion people worldwide are at risk for IDD. Of these, 30-70% have goiter and 1-10% have cretinism. Two decades ago the I.R. Iran was among the countries most severely affected by iodine deficiency, but during the last two decades has made much progress in the development of universal salt iodization strategies and IDD prevention, and since 1996 meets all WHO/UNICEF/ICCIDD criteria for the sustainable elimination of iodine deficiency.