The protein and amino acids (AAs) metabolism are known to be impaired in the uremic patients. The etiology of those abnormalities is multifactorial, such as inadequate nutritional intake, protein-restricted diet, decreased urinary excretion of AAs, impaired activity of AAs-synthetic and/or-degrading enzymes, disturbed absorption, loss of AAs during dialysis, and abnormal transcellular movement due to hormonal abnormalities. As the nutritional supplement for the uremic patient, essential amino acid has been proposed. It was, however, reported to cause the hyperammonemia with or without encephalopathy in addition to fatty liver. Further investigation concerning the optimal composition of AAs solution for uremic patients is required to solve these problems.