Hepatorenal syndrome (HRS) is a major complication of patients with cirrhosis, with the annual incidence in patients with ascites being approximately 8% []. This syndrome develops in the latest phase of the disease and there is now evidence that it is an important determinant of patient survival. Many aspects of HRS are, however, still poorly understood. There are two types of HRS: type 1 or progressive HRS which is associated with a very poor prognosis (median survival rate lower than 2 weeks), and type 2 HRS which is characterized by a steady impairment in circulatory and renal function. The pathogenesis of HRS is a deterioration in effective arterial blood volume due to splanchnic arterial vasodilation and a reduction in venous return and cardiac output. It is therefore not surprising that the syndrome can be reversed by the simultaneous intravenous administration of albumin and arterial vasoconstrictors. Intrarenal mechanisms are also important and require prolonged improvement in circulatory function to be deactivated. Long-term administration of intravenous albumin and vasoconstrictors or the correction of portal hypertension with a transjugular intrahepatic portacaval shunt are effective in the treatment of HRS. They also appear to improve survival and may serve as a bridge to liver transplantation, which is the treatment of choice in these patients.