Hepatorenal syndrome (HRS) is a serious complication of liver cirrhosis with critically poor prognosis. The pathophysiologic hallmark is severe renal vasoconstriction, resulting from complex changes in splanchnic and general circulations as well as systemic and renal vasoconstrictors and vasodilators. Rapid diagnosis and management are important, since recent treatment modalities including vasoconstrictor therapy can improve short-term outcome and buy time for liver transplantation, which can result in complete recovery.