The proper diagnosis of hyponatremia is a vital component of the perioperative care of liver transplant patients, as hyponatremia is common among patients with end-stage liver disease. The general recommendation for the treatment of chronic hyponatremia is to limit the speed of correction. Unfortunately, the peri-transplantation period is often punctuated by large fluctuations in serum sodium concentration, which increases the risk of neurologic complications and osmotic demyelination syndrome. Consequently, the therapeutic goals and management strategies for hyponatremia vary greatly between the pre-transplantation, intraoperative, and post-transplantation periods. In this chapter, the definition, prognosis, pathophysiology, and treatment of hyponatremia in patients with cirrhosis are reviewed.