Ichthyoses belong to the group of genodermatoses, characterized by hyperkeratosis and desquamation of the epidermis. Clinical manifestation is heterogeneous and depends on the type of the disease. Harlequin foetus is the most severe form of congenital ichtyosis, inherited as an autosomal recessive trait. The disfunction of the epidermis begins prenatally. Neonates are often born prematurely, in severe condition. At present better care and treatment prolong the length and quality of children's life. We report a case of harlequin ichthyosis. Parents were healthy and there was no history of ichthyosis or other congenital anomalies in the family. Sonography at the 26th week of gestation revealed anomalies of the fetal face; however, the diagnosis of harlequin ichthyosis was not established prenatally. The male child was born alive at the 37th week of the third pregnancy, with birth weight of 2900g. Typical features of harlequin ichthyosis were present at birth. Intensive neonatological care was necessary. The child survived and at the time of the report was 6 months old and in good condition.