The annual incidence of acute kidney injury (AKI) has been increasing as the population ages. Despite advances in critical care and dialysis technology, the mortality remains unacceptably high in patients with AKI during the past few decades. Renal replacement therapy (RRT) is performed to treat patients with severe AKI and multiple organ failures, as well as to remove fluid in patients with fluid overload including those with acute heart failure and lung edema in the intensive care unit (ICU). The mortality in patients with AKI requiring RRT is higher than 50 %. RRT strategies in patients with AKI depend on various conditions. However, there is little consensus on when to start and stop RRT, its optimal dose, and the choice of different RRT modalities (intermittent versus (vs.) continuous) in patients with AKI. Patients with AKI in the ICU are preferentially treated with continuous rather than intermittent RRT (IRRT), usually because of hemodynamic stability and steady of solute clearance. At present, the type and dose of RRT are dependent on the experience of the attending clinicians, including intensivists and nephrologists.