Background: Sepsis-associated acute kidney injury (SA-AKI) is an acute kidney injury in the presence of sepsis without other significant contributing factors explaining acute kidney injury (AKI). Circulating syndecan-1, angiopoietin-2, and urinary neutrophil gelatinase-associated lipocalin levels can potentially cause neglected AKI to become acute kidney disease (AKD) and even chronic kidney disease (CKD). Therefore, studying its levels in the early phase of AKI is important, especially in SAAKI. Objectives: This study aims to analyze the levels of syndecan-1, angiopoietin-2, and urine neutrophil gelatinase-associated lipocalin (uNGAL) as other modalities that might detect AKI earlier in children with SAAKI. Methods: This study enrolled 23 children between one month and 18 years with sepsis. Blood samples were collected from all patients at the baseline, 12, 24, and 48 hours after admission to assess serum creatinine, syndecan-1, angiopoietin-2, and a urine sample was collected to measure uNGAL levels. We used the Wilcoxon signed-rank test to compare each biomarker with the time of measurement and the Mann-Whitney test to compare the levels of biomarkers with the incidence of SA-AKI. Results: The highest median value for uNGAL was 78.30 (3.20 - 24098.40) in the 12th-hour measurement; for syndecan was 2.92 (0.06 - 83.00) in the baseline measurement, slightly decreased and continued to increase up to 48 hours, and for Ang-2 was 4159.60 (17.60 - 226428.00) in the 12th-hour measurement. The incidence of SA-AKI based on the pediatric risk-injury-failure-loss-end stage (pRIFLE) criteria were that five children (21.7%) had AKI in the risk/injury phase at baseline, 24-hour, 48-hour observations, and also six children (26.1%) at 12-hour observation. Conclusion: There was an increase in levels of syndecan-1 and ang-2 in children with severe sepsis, especially in the first 24 hours.