Tumor lysis syndrome (TLS) is an oncologic emergency due to the rapid lysis of tumor cells and subsequent release of large amounts of intracellular potassium, phosphate, and uric acid into the bloodstream. Precipitation of uric acid and/or calcium phosphate crystals in the renal tubules can result in acute kidney injury. TLS is frequently observed in children with malignancy, which has high tumor burden, rapid cell turnover or high chemosensitivity (particularly, Burkitt's lymphoma and acute lymphoblastic leukemia), following the initiation of cytotoxic therapy. The current recommendations for prophylaxis and management are based on the TLS risk stratification. It is essential to administer adequate fluid and hypouricemic agents (allopurinol and/or rasburicase) to prevent acute kidney injury. In children susceptible to TLS, prompt diagnosis and aggressive treatment, such as renal replacement therapy, should be performed through close monitoring.