Continuous renal replacement therapy (CRRT) has become the preferred dialysis modality to support critically ill children with acute kidney injury. As CRRT technology and clinical practice advances, experiences using CRRT on small infants and neonates have increased. In neonates with hyperammonemia or acute kidney injury during extracorporeal membrane oxygenation (ECMO) therapy, CRRT can be a safe and effective technique. However, there are many limitations of CRRT in neonates, including vascular access, bleeding complications, and lack of neonatespecific devices. This review discusses the basic principles of CRRT and the special considerations when using this technique in neonates and infants.