Acute kidney injury (AKI) can result in mortality or progress to chronic kidney disease in hospitalized patients. Although serum creatinine has long been used as the best biomarker for diagnosis of AKI, it has some clinical limitations, especially in children. New biomarkers are needed for early diagnosis, differential diagnosis, and reliable prediction of prognosis in AKI. Up to the present, candidate AKI biomarkers include neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), interleukin-18 (IL-18), livertype fatty acid-binding protein (L-FABP), matrix metalloproteinase-9 (MMP-9), and Nacetyl-$ss$-D-glucosaminidase (NAG). However, whether these are superior to serum creatinine in the confirmation of diagnosis and prediction of prognosis in AKI is unclear. Further studies are needed for clinical application of these new biomarkers in AKI.