X-linked congenital adrenal hypoplasia (CAH) is one of the most widespread forms of congenital hypocortisolism in boys. The disease is caused by defects in the NR0B1 gene that encodes for DAX1 protein. CAH manifests itself largely as adrenal insufficiency in young children and hypogonadotropic hypogonadism developing by the pubertal period. This paper describes 10 patients presenting with X-linked form of congenital adrenal hypoplasia. In six of them adrenal insufficiency was apparent during the first month of life and in the remaining four at a later time (up to the age of 13 years). Hypogonadism was diagnosed in all the patients (n=7) who reached the age of 15 by the moment of the last examination. Diagnosis of CAH was confirmed by molecular genetic analysis in all the ten cases. Nine different mutations in the NR0B1 gene were identified.