Pediatric patients with cancer are known to experience AKI but its incidence and clinical impact has not been well established. The purpose of this study was to analyze the incidence of AKI in pediatric patients with cancer within 1 year of cancer diagnosis, and to assess its impact on survival and the development of chronic kidney disease (CKD) defined as eGFR below 60 ml/min/1.73msup＞2/sup＞. Retrospective review of medical records was done on patients who were treated for cancer at Seoul National University Hospital between 2004 and 2013. Patients aged 18 years old or younger at cancer diagnosis and had their creatinine level measured at diagnosis and at least one more time by October 2015 were eligible for this review. AKI was defined according to the Kidney Disease: Improving Global Outcomes (KDIGO) criteria: stage 1 as 33.3% decrease of estimated glomerular filtration rate (eGFR) from baseline, stage 2 as 50% decrease, stage 3 as 66.7% decrease or eGFR below 35 ml/min/1.73msup＞2/sup＞. Among 2,552 candidate patients assessed, 1,382 patients (M:F 805:577) were eligible for this review. Patients were diagnosed with hematological malignancies, brain tumors, or solid tumors at a median age of 8.35 years old. Their median eGFR at diagnosis was 95.1 mL/min/1.73msup＞2/sup＞ and a total of 817 patients (59.1%) developed AKI within 1 year of cancer diagnosis. Of these patients, 40.8%, 34.1%, and 25.1% had stage 1, stage 2, and stage 3 AKI respectively. The incidence of AKI was highest in patients with acute myeloid leukemia (86.8%), followed by those with primitive neuroectodermal tumor (81.6%), and those with hepatoblastoma (77.4%). The incidence of AKI was lowest in patients treated for Langerhans cell histiocytosis (26.7%). The mortality rate of the patients was 20.8%, and stage 3 AKI (adjusted HR 1.90, 95% CI 1.26 – 2.85) was found to be an independent risk factor of mortality. CKD developed in 2.9% of the survivors and the need for renal replacement therapy (RRT) at the time of AKI of any duration (adjusted OR for RRT 1 weeks: 10.04, 95% CI 1.43 – 45.46, adjusted OR for RRT ≥ 1 week: 22.01, 95% CI 3.82 – 117.69) was an independent risk factors of developing CKD. In conclusion, AKI occurs in a large percentage of pediatric patients with cancer and adversely affects both their survival and their long-term kidney function.