Hypernatremia is one of the commonly syndromes in critically ill patients. Severe hypernatremia has a low incidence (0.6%–1.0%) but with a very high mortality (58%–87%). Conventional treatments include the limitation of sodium intake and the supplement of sodium free liquid according to the assessed water lost. The reduction rates of conventional treatments are commonly not effective enough to decrease the serum sodium concentration in severe euvolemic or hypervolemic hypernatremia patients. Continuous renal replacement therapy (CRRT) has been reported to be effective on the reduction of sodium level in severe hypernatremia patients. However, the evidences on the use of CRRT for hypernatremia are limited. Our present review summarizes the current evidences on the prevalence of hypernatremia, the outcome of hypernatremia patients, the conventional treatment of hypernatremia, and the advantages and indications of CRRT for the management of hypernatremia. Additionally, we introduce our experiences on the management of hypernatremia using CRRT as well.