Iron deficiency and iron deficiency anemia remain a major and global public health problem that affects particularly infants, young children, and women of childbearing age in developing countries. The prevalence of iron deficiency anemia is still common in industrialized countries despite efforts to improve public awareness and strengthen programs for the prevention and control of iron deficiency. The most common risk factors for iron deficiency in early childhood are rapid growth, perinatal risk factors, poor dietary intake, and gastrointestinal blood loss due to excessive consumption of cow’s milk. Iron deficiency and iron deficiency anemia cause a wide variety of symptoms and changes in many different tissues. The most concerning consequences of iron deficiency in children are the alterations of cognitive, motor, and behavioral performance. Persistent neurocognitive changes despite iron repletion have increased the importance of prevention and early detection of iron deficiency. The main principles of treatment include investigation and elimination of the underlying cause, iron supplementation, improvement of nutrition, and education of the patient and family. Oral iron supplements are desirable as first-line therapy. Follow-up is very important to confirm the diagnosis and to ensure that anemia is adequately treated.