Background: Deficiency of thyroid hormones at any time from the first weeks of life to two years after birth can impair the growth and activity of brain cells and affect brain function and intelligence. Numerous evidences show the benefits of the breast feeding in prevention of many medical conditions for child.  While congenital hypothyroidism is linked to prenatal circumstances, mostly related to maternal factors, later hypothyroid diseases in infants might be associated to nutritional status of the newborn. In this study we reviewed different aspects of the breast feeding or formula feeding in relation to the hypothyroidism in early childhood.