Congenital adrenal hyperplasia (CAH) is an autosomal recessive defect in steroidogenesis, mostly affecting 21-hydroxylase enzyme deficiency. The other seldom cortisol synthesis abnormalities include deficiencies of: 11beta-hydroxylase, 3beta-hydroxysteroid dehydrogenase, 17beta-hydroxylase, 17,20-lase and 11 beta-hydroxysteroid dwehydrogenase type 1. There are three main types, depending on the clinical level of 21-hydroxylase deficiency: (1) classical form--salt-wasting CAH (2) the classical form non- salt-wasting (3) non-classical form. CAH incidence is estimated at 1/14 000-1/10 000, of which about 70% is the classic salt-wasting form. The clinical picture varies considerably depending on the form. In the classic salt-wasting CAH may develop into the a shock. In classic CAH without loss of salt dominates virilization in girls and precocious puberty in boys. A non-classical forms usually presents as hyperandrogenisation and fertility. CAH treatment is mainly based on the use of glucocorticoid therapy, and if necessary supplemented mineralocorticoids. There is also potential to consider prenatal treatment (female fetuses diagnosed as CAH) with the use of dexamethason. However this kind of treatment is related to some medical and ethical controversies.