The past few years have seen several substantial advances in our understanding of the importance of micronutrients in child health and nutrition. Although historically child nutrition in developing countries has focused on protein and energy sufficiency, more recent efforts have been made to evaluate and eliminate micronutrient deficiencies. Accumulating data have underlined the important long-term health effects that may occur with iron deficiency, and studies continue to confirm the benefits of successful treatment of iron deficiency anemia. Zinc is another micronutrient whose significance to child health is increasingly appreciated. Although breakthroughs in micronutrient research have generally come from populations in developing countries, children in industrialized countries also benefit from increasing knowledge about nutritional requirements and interventions.