The mortality rate of critically ill patients with severe acute kidney injury (AKI) remains high. The associated sepsis and septic shock, as well as the presence of multiorgan failure, further increase the risk of death. Renal replacement therapy (RRT) represents the cornerstone of the management of severe AKI. Continuous RRT (CRRT) has been considered the predominant form of dialysis in the intensive care unit due to its accurate volume control, steady acid-base, and electrolyte correction and achievement of hemodynamic stability. This narrative review covers an introduction to CRRT, its physiologic principles, modalities, requirements, indications, and different elements of adequate prescription.