The purpose of our study was to apply the new classification criteria proposed by the Acute Kidney Injury Network (AKIN) in a pediatric population and to determine the clinical characteristics, laboratory features and outcomes of acute kidney injury (AKI) in a tertiary pediatric nephrology center in Turkey. Patients' charts from January 2003 to August 2008 were retrospectively evaluated. One hundred patients (55 male; 45 female) were enrolled. Median age at the time of AKI was 7 years (range 1 month-18 years). Patients' AKI was classified according to the staging system as follows: 25% stage 1, 36% stage 2 and 39% stage 3. The etiology of AKI was bone marrow transplantation related in 27%, renal disease in 14%, dehydration in 10%, nephrotoxic medication in 8%, cardiac surgery related in 8%, and congenital anomalies in 2%. Multiple etiologic factors with underlying chronic diseases were present in 31% of the patients. Dialysis was needed in 45% of the patients. Mortality rate was 33%. Dialysis need and mortality rate were higher in stage 2 and stage 3 patients, with a more favorable prognosis in stage 1 patients. Mortality rate was higher in patients that had undergone cardiac surgery and in those with multiple etiologic factors. The proposed AKIN staging successfully reflected the course of patients with AKI. The underlying cause of AKI seemed to be an important risk factor for death.