Purpose — to demonstrate the features of the course and treatment of Gilbert's syndrome in a newborn. Materials and methods. We present A clinical case of follow-up of a newborn with Gilbert's syndrome. The paper examines the features of the course and treatment of this disease. Results. Important is the fact that the difficulties in diagnosing Gilbert's syndrome in newborns are primarily due to current problems in neonatology, namely the diagnostics of pigmentary disorders that occur during bilirubin metabolism. The polymorphism of Gilbert's syndrome symptoms and the lack of a clear association with plasma bilirubin levels make it difficult to diagnose the disease, especially in newborns. The peculiarity of the course of Gilbert's syndrome in the given case is as follows: early onset of the disease (from the day of birth), the presence of high hyperbilirubinemia (total bilirubin — 189.2 μmol/l, direct bilirubin — 24.3 μmol/l, indirect bilirubin — 164.9 μmol/l), intermittent attacks of jaundice. The severity of the disease is also due to the transient condition of the newborn: hypoxic and ischemic lesions of the CNS, transient dysfunction of the adrenal cortex, open oval window, and the mother's failure to follow clear principles of treatment of Gilbert's syndrome in breastfed infants. Conclusions. The peculiarity of this disease is the fact that the mother is at risk of giving birth to a sick child due to a burdened hereditary history of the paternal line (Gilbert's syndrome). Therefore, it is necessary to provide medical and genetic counseling when planning the birth of a child to determine the degree of risk of birth with this disease. The research was carried out in accordance with the principles of the Helsinki Declaration. The informed consent of the patient was obtained for conducting the studies. No conflict of interest was declared by the authors. Key words: Gilbert's syndrome, hyperbilirubinemia, a newborn.