Abstract: Sixteen amino acids were determined in the fasting blood of individuals of various ages by the use of Hitachi 835-50 automatic amino acids analyzer.The significant differences were seen among young adults and men over 65 years individual in different neutritional status.Of the essential amino acids,valine,leucine,isoleucine,methyonine,lysine were found to be significantly lower in older subjects and in young adults with average neutritions.The results suggested that there is an increased requirement for essential amino acids in the aged especially branched-chain amino acids and lysine.Sufficient supplement with these amino acids is necessary.