Thyroid hormones are crucial for normal development of a child from early foetal life. They have an impact on the development of the central nervous system, both prenatally and up to the age of 3 years, and regulate growth and most metabolic processes. Their importance has led to the introduction of screening for congenital hypothyroidism, which has been conducted in Poland for over 40 years. The diagnosis of congenital hypothyroidism necessitates immediate levothyroxine implementation and strict treatment monitoring. Thanks to iodine prophylaxis, children in Poland do not require additional iodine administration. An isolated increase in thyroid-stimulating hormone concentration without clinical signs of hypothyroidism and with negative antithyroid antibodies does not require treatment, but only monitoring of thyroidstimulating hormone levels. Children with positive antithyroid antibodies, genetic syndromes that predispose to hypothyroidism and history of thyroid irradiation require more frequent controls. The recommendations for suspected hypothyroidism presented in this article are based on the European Thyroid Association guidelines from 2014 on the management of subclinical hypothyroidism in children and pregnant women.