BACKGROUND AND AIMS: Sepsis is the main cause of death from infection. This study aimed to determine whether neutrophil gelatinase-associated lipocalin (NGAL) values better predict mortality in septic patients when combined with inflammation-based prognostic scores. MATERIAL AND METHODS: Forty-four adult patients diagnosed according to the Sepsis-3 definition and who were admitted to the ICU were prospectively examined from June 2018 to November 2018. Urine samples were collected from each patient with a urethral balloon bag to measure NGAL after ICU entry at the following time points: immediately after and 2, 3, and 4 days after ICU entry. The Glasgow Prognostic Score, the neutrophil to lymphocyte ratio (NLR), the platelet to lymphocyte ratio, the Prognostic Nutritional Index, the Prognostic Index (PI), the Sequential Organ Failure Assessment (SOFA), and quick SOFA were examined immediately after ICU entry. Predictors of mortality were assessed by receiver operating characteristics curve (ROC) analysis, log-rank test, and multivariate logistic regression analysis. RESULTS: NGAL on day 4 (AUC: 0.94) and ΔNGAL from day 4 to day 1 (AUC: 0.9) for 28-day mortality; NGAL on day 4 (AUC: 0.94) and inflammation-NGAL score (iNS) NGAL-PI (AUC: 0.69) for 60-day mortality; ΔNGAL from day 3 to day 1 (AUC: 0.82) for 90-day mortality; and iNS NGAL-NLR (AUC: 0.71) and iNS NGAL-PI (AUC: 0.68) for in-hospital mortality were found to be predictors of mortality by ROC curve analysis. NLR (p = 0.02) for 28-day mortality; NGAL on day 2 (p = 0.031), ΔNGAL from day 2 to day 1 (p = 0.013), and NLR (p < 0.0001) for 60-day mortality; NGAL on day 2 (p = 0.017), ΔNGAL from day 2 to day 1 (p = 0.014), and NLR (p = 0.033) for 90-day mortality; and NGAL on day 2 (p = 0.007) for in-hospital mortality were found to be predictors of mortality by log-rank test. iNS NGAL-NLR (OR, 0.024; p = 0.019) for 60-day mortality and NGAL from day 3 to day 1 (OR, 1.005; p = 0.013) for 90-day mortality were found to be predictors of mortality by multivariate logistic regression analysis. CONCLUSIONS: NGAL and ΔNGAL were predictors of mortality in sepsis patients on day 2 after ICU entry and thereafter, but not on day 1.