Objective To analyze the relationship between umbilical cord blood chemokines regulated upon activation normal T cell expressed and secreted(RANTES),C-X-C motif chemokine ligand 12(CXCL12),C-X-C motif chemokine receptor 4(CXCR4)and neonatal septicemia inflammatory response and outcome.Meth-ods A total of 242 children with neonatal septicemia admitted to a hospital from January 2020 to January 2024 were selected as the study subjects,and were divided into non-critical group(101 cases),critical group(79 cases)and extremely critical group(62 cases)according to neonatal critical case score.According to the prognosis,the subjects were divided into good prognosis group and bad prognosis group.The levels of RAN-TES,CXCL12,CXCR4 and inflammatory factors[C-reactive protein(CRP),interleukin-6,IL-1β]in umbilical cord blood of each group were detected.The correlation between RANTES,CXCL12,CXCR4 and inflammato-ry factors in umbilical cord blood of neonatal septicemia was analyzed by Pearson correlation,and the influen-cing factors of poor prognosis of neonatal septicemia were analyzed by multivariate Logistic regression.Re-ceiver operating characteristic(ROC)curve was drawn to analyze the value of umbilical cord blood RANTES,CXCL12 and CXCR4 in predicting the poor prognosis of neonatal septicemia.Results The levels of RAN-TES,CXCL12,CXCR4,CRP,IL-6 and IL-1β in umbilical cord blood of extremely critical group were higher than those of critical group and non-critical group,and the differences were statistically significant(P＜0.05).The levels of RANTES,CXCL12 and CXCR4 in umbilical cord blood of neonatal septicemia were posi-tively correlated with CRP,IL-6 and IL-1β(P＜0.05).Multivariate Logistic regression analysis showed that extremely severe,early-onset septicemia,high RANTES,high CXCL12 and high CXCR4 were risk factors for poor prognosis of neonatal septicemia(P＜0.05).ROC curve analysis results showed that the area under the curve(AUC)of umbilical cord blood RANTES,CXCL12 and CXCR4 in predicting poor prognosis of neonatal septicemia were 0.810,0.814 and 0.763,respectively,and the AUC of three indicators combined prediction was 0.914,which was higher than that of single prediction.Conclusion The increased levels of RANTES,CX-CL12 and CXCR4 in umbilical cord blood of neonatal septicemia are associated with inflammation,aggravation and poor prognosis,and the combination of RANTES,CXCL12 and CXCR4 can predict the risk of poor prog-nosis of neonatal septicemia.