The role of continuous renal replacement therapy (CRRT) has been expanding beyond support for acute kidney injury (AKI) in recent years. Children with malignancy are particularly at risk of developing conditions that may require CRRT. We reported three children with malignancy who received CRRT for non-AKI indications. Patient 1 was a 17-year-old teenage girl who developed refractory type B lactic acidosis due to relapse of acute lymphoblastic leukemia (ALL). Her peak lactate level was 18 mmol/L, and the lowest pH and bicarbonate level was 7.13 and 6.0 mmol/L, respectively. She received three sessions of high-volume hemodiafiltration to bring down the lactate level. Patient 2 was a 15-year-old male with T-cell ALL who developed cytokine storm requiring mechanical ventilatory and high-dose inotropic support due to necrotizing enterocolitis complicated by pneumoperitoneum and Klebsiella pneumoniae septicemia. He received two sessions of hemoperfusion using a specific filter capable of endotoxin absorption and cytokine removal and was successfully weaned off all inotropes after the treatment. Patient 3 was an 8-year-old boy who received bone marrow transplantation and developed worsening hyperbilirubinemia and deteriorating liver function. He received a session of single-pass albumin dialysis for bilirubin removal prior to liver biopsy. Except for mild electrolyte disturbances, no major CRRT complication was encountered. Our report demonstrated that CRRT is an effective and safe procedure for a wide spectrum of nonrenal conditions among children with oncological diagnoses in the pediatric intensive care unit. However, the optimal dose, regime, timing of initiation, and monitoring target for these indications remain to be determined.