Background: Infections are one of the most important causes of neonatal morbidity and mortality. Clinical symptoms are not specific and routinely used laboratory tests do not allow to recognize infection in all positive cases and exclude it in the others. The aim of the study was to test the usefulness of IL-6 and IL-1ra in the diagnosis of early onset sepsis in premature newborns. Material/Methods: 22 premature newborns with infection and 25 sick, not-infected controls were enrolled. All patients were routinely tested for white blood and neutrophils count, I/T ratio, serum levels of CRP, PCT, IL-6 and IL-1ra at admission on the first day of life, after 24 and 72 hours.Results: The median values of IL-6 and IL-1ra in the infected group were significantly higher at admission. CRP in the infection group raised after 24 h (p

Keywords: IL- 1 receptor antagonist, CRP, IL-6, procalcitonin, Infection, newborns