Iodine is an important micronutrient for humans. This element is a necessary component of thyroid hormones. An insufficient dietary supply of iodine results, in the development of a variety of disorders grouped under the general heading of Iodine Deficiency Disorders (IDD), a worldwide health problem. The multifactorial nature and complex interactions of environmental conditions with host factors in the pathogenesis of endemic goiter constitutes a major challenge to the understanding and control of the problem in endemic areas. Endemic goiters constitute the most spectacular disorder from the clinical and epidemiological points of view. The control mechanism of thyroid gland, pathophysiology and epidemiology of the endemic goiter and strategies toward eradication of iodine deficiency at the end of this century, is described.