Patients with advanced cirrhosis frequently develop dilutional hyponatremia due to impairment of their renal ability to eliminate solute-free water. Although the pathophysiology of this disorder is multifactorial, an increased hypersecretion of arginine vasopressin (AVP) is a major factor. The prevalence of hyponatremia in cirrhosis, as defined by a serum sodium level of 130 mmol/L is reported to be about 20%, and there are several lines of evidence that hyponatremia is a risk factor for the development of hepatic encephalopathy, and that it predicts a poor quality of life independent of liver function. Hyponatremia also predicts short-term mortality in cirrhotic patients awaiting liver transplantation. The principle of the management of hypervolemic hypona- tremia is to induce a negative water balance, with the aim of normalizing the increased total body water, which would result in an improvement in serum sodium concentration. Fluid restriction is the most widely accepted nonpharmacological therapy, but its efficacy is very limited. The administration of hypertonic sodium chloride has been common in severe hypervolemic hyponatremia, but its effect is only partial and short lived; moreover, additional expansion of fluid can worsen ascites and edema. Therefore, the pathophysiologically oriented treatment of hyponatremia focuses on inhibiting the actions of AVP. Recently, antagonists of the V2 receptors of vasopressin has been proposed to manage hyponatremic patients, such as heart fauilure, syndrome of inappropriate antidiuretic hormone or liver cirrhosis. Especially, a lot of hyponatremic patients with cirrhosis had ascites, and some of them had intractable ascites. In these patients, antagonists of the V2 receptors of vasopressin including tolvaptan might have beneficial effect in enhancing not only hyponatremia , but also ascites