The heel-prick test in newborn babies has vastly improved the prospects for babies born with hypothyroidism. The vast majority of children who are detected and treated promptly grow up normally. Babies and children with hypothyroidism should be seen regularly by a pediatric endocrinologist or a pediatrician with a special interest in endocrinology. Medication must be taken regularly and usually for life. The dose will need to be adjusted as your child grows and so regular blood tests are important. It is well recognized that thyroid problems often run in families and if family members are unwell they should be encouraged to discuss with their own GP whether thyroid testing is warranted. Congenital hypothyroidism (CH) is the commonest endocrine and most treatable cause of mental retardation. Laboratory diagnosis must be made soon after birth, and effective treatment initiated promptly to prevent irreversible brain damage. The advent of neonatal screening programs for congenital hypothyroidism has dramatically improved the prognosis for affected infants. The goal of newborn screening is to detect CH and begin treatment before the infant reaches one month of age