Abstract: Objective To test the predicative roles of neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1( KIM-1 ) for acute kidney injury (AKI) in critically ill patients. Methods Children from pediatric intensive care unit, were randomly divided into four groups: critically ill patients with AKI (group 1 ), critically ill patients with non- AKI (group 2) , chronic kidney disease group (group 3), healthy control group (group 4). 1.5 ml venous blood and urine specimens were collected and kept under -70°C. Serum creatinine , urine NGAL and urine KIM-1 were analyzed. Results Compared with group 2, group 3 and group 4, the urine NGAL and urine KIM-1 increases obviously in group 1 (P<0.05). There is no significance of urine NGAL and urine KIM-1 between group2, group3 and group 4 (P> 0.05). The concentration of urine NGAL increased more than 10 times of base-line level 2 days before the diagnosis of AKI under the Acute Kidney Injury Network standard with area under curve (AUC) 0.955 (P <0.05) , and the concentration of urine KIM-1 increased more than 5 times of base-line level 1 day before AKI with AUC 0.878 (P <0.05). The AUC was 0.984 (P <0.01) when they were combined. There is negative correlation between the increased times of urinary KIM-1, urinary NGAL and vally value of creatin clearance rate. Conclusions The concentrations of urine NGAL and urine KIM-1 are useful early biomarkers for predicting AKI, especially when they were combined.