Iodine Deficiency Disorders (IDD) can be prevented by an adequate intake of iodine in the population. Monitoring and evaluation are the most important phases of an IDD control program. The consequences of iodine deficiency are goiter and subclinical/clinical hypothyroidism in pregnancy. The deficiency is an important risk factor for brain damage and motor-mental development in the fetus, the neonate and in the child. In order to assess IDD, control programs should be developed, followed up and evaluated. The recommended methods of assessing status are; assessment of the goiter rate, measurement of urinary iodine concentration, determination of thyroid hormone levels and of thyroslobulin. Although adequate technology exists, elimination programs for IDD have not been successful until recent years. The most important issue at present is the long-term sustainability of salt iodization programmes. Alternative strategies are also needed for iodization in areas where iodized salt will not be available in the foreseeable future.