BACKGROUND: Previously, not six systemic inflammatory indices were evaluated in the diagnosis of early onset sepsis (EOS) in very low birth weight (VLBW, <1500g) premature infants. OBJECTIVES: We evaluated the effectiveness of systemic inflammatory indices in the diagnosis of EOS in VLBW infants. METHODS: Premature infants with birth weight <1500 g were included in the study. Six systemic inflammatory indices including neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), monocyte-to-lymphocyte ratio (MLR), systemic immune-inflammation index (SII), pan-immune-inflammation value (PIV), and systemic inflammation response index (SIRI) were compared in patients with EOS (treatment group) and without EOS (control group). RESULTS: Of 917 infants enrolled, 204 infants were in the EOS group and 713 infants comprised the control group. NLR, MLR and SIRI values were significantly higher in the EOS group than in the control group (p < 0.001). The AUC value of SIRI for the predictivity of EOS was 0.803. CONCLUSIONS: The SIRI can be used together with other parameters as both an easily accessible and the reliable systemic inflammatory indices in the diagnosis of EOS in VLBW preterm infants.