Introduction. The study of the mechanisms of adaptation and consequences of deadaptation in newborns, and especially premature babies in the first days of life is an integral part of neonatal practice. The cytokine system is considered as sensitive and informative indicators of homeostatic disorders in newborns of different gestational ages.Aim. To assess the features of the early neonatal period in newborns of different gestational ages according to the nature of changes in the levels of interleukin-1, -4, -8 in the cord blood and on the 3-4th day of the infant's life.Materials and methods. 108 newborns were examined, of which 64 premature infants of the gestational age of 32 (0/7) - 36 (6/7) weeks were included in the treatment group: moderately premature infants (32 (0/7) - 33 (6/7) weeks) and late premature infants (34 (0/7) - 36 (6/7) weeks). The control group included 44 conditionally healthy full-term infants born between 37 (0/7) and 41 (6/7) week of gestation: early full-term (37 (0/7) - 38 (6/7) weeks) and full-term intants (more than 39 (0/7) weeks).Results and discussion. The full-term infants, as well as late premature infants, whose clinical status was assessed as satisfactory, usually showed minimum levels of all studied cytokines. If the early neonatal period was complicated, high levels of interleukin-1 and -8 with underlying slightly elevated levels of anti-inflammatory interleukin-4 were observed. This fact supports the activation of cytokine reactions during manifestation of pathological symptom groups generated by various organs and systems in the early neonatal period.Conclusion. The nature of cytokine reactions can serve as a marker of unfavourable course of the early neonatal period in premature infants and a criterion that justifies the implementation of necessary corrective measures.