Abstract: OBJECTIVE To explore the value of time to positive (TTP) in differential diagnosis of coagulase-negative Staphylococcus (CoNS) bloodstream infection (BSI) and contamination in juveniles, including the neonates (less than 28 days) and the children (less than 16 years). METHODS From Jan 2015 to Sep 2017, a total of 160 patients (45 neonates and 115 children ), the blood specimens of whom the CoNS strains were isolated, were retrospectively analyzed, the enrolled subjects were divided into the infection group and the contamination group, the TTP was compared between the two groups, the receiver operating characteristic (ROC) curve was drawn to determine the optimal threshold value of TTP in differential diagnosis of the CoNS BSI, and the diagnostic efficiency was evaluated. RESULTS The TTP was (17.32±5.96)h in the neonatal infection group, (21.17±5.26)h in the neonatal contamination group, and there was significant difference (t=2.170,P=0.032); the TTP was (20.72±7.70)h in the children infection group, (26.20±13.20)h in the children contamination group, and there was significant difference (t=2.820,P=0.014).The ROC curve analysis showed that more than 17.67 h of TTP was the optimal threshold value for the identification of BSI and contamination in the neonates, the area under curve (AUC) was 0.74, the sensitivity was 71.00%, the specificity was 85.10%; more than 17.35 h of TTP was the optimal threshold value for the identification of BSI and contamination in the children, the AUC was 0.67, the sensitivity was 31.50%, and the specificity was 97.60%. CONCLUSION The TTP has the medium accuracy in the differential diagnosis of CoNS BSI in the neonates, the diagnostic efficiency is low for the children, however, specificities are both high, and the TTP has certain value in the identification of the CoNS BSI and contamination in the juveniles.