Liver disease and nutritional status are known to affect each other. When liver disease is severe, patients become more malnourished and have a worse prognosis. Adequate nutritional support for patients with liver diseases can improve a patient’s condition and prognosis. In acute liver failure, malnutrition is uncommon, and the disease prognosis is determined within a short time. Patients with acute liver failure may survive and recover if they receive a transplant. Considerations should be given to the management of glucose intolerance and hyperammonemia. However, well-designed clinical trials are still lacking until now. In the case of liver cirrhosis, malnutrition may occur due to a variety of causes, and as in other diseases, oral or enteral nutrition is preferred to parenteral nutrition. Even if esophageal varices are present, it is possible to install a feeding tube. However, in the presence of ascites, PEG (percutaneous endoscopic gastrostomy) becomes contraindicated due to risk of complications. Calorie intake of 30~35 Kcal/kg/day and protein intake of 1.2 to 1.5 g/kg/day are appropriate. Protein restriction should not be necessary unless hepatic encephalopathy is severe. Late evening snacking and intake of branched chain amino acids can be helpful.