Background: Acute kidney injury (AKI) is a serious clinical condition in children admitting to the pediatric intensive care unit. Beside having the risk of significant morbidity and mortality, AKI has also increased the risk for chronic kidney disease. However, there is paucity of data regarding AKI epidemiology in children. Herein, we aimed to describe the incidence, risk factors, and outcome of AKI in critically ill children. Methods: The records of patients, who were hospitalized in our pediatric intensive care unit between October 2016 and March 2018 were investigated retrospectively. The relationship between AKI and the need of invasive mechanical ventilation and non-invasive mechanical ventilation, inotropic and nephrotoxic drug use, initial laboratory findings, continuous renal replacement need, pediatric risk of mortality-III score (PRISM-III), duration of hospitalization, and mortality rate were investigated. Results: Totally, 447 patients were found to have been included in the study. The AKI developed in 111 patients. The sepsis was the most common underlying disease with 27 patients (24.3 %). There was a statistical significance between development of AKI and the need of invasive mechanical ventilation, inotropic and nephrotoxic drug use, PRISM-III score, continuous renal replacement need, plasma exchange, blood component transfusion, duration of hospitalization, and mortality. Conclusions: The AKI is associated with prolonged hospitalization and increased mortality. AKI should be considered as a medical emergency that should be diagnosed and managed accurately.