Abstract: Chlorella and Scenedesmus are two kinds of unicellular algae containing much amount of protein, and the mass culturing of them seems very feasible. It is noted in recent years, therefore, that the algae are very superior protein sources for Japanese people.The analyses were conducted for determination of amino acid contents in the algae to examine the nutritive value as a source of protein and microbiological assay was used for the determination of 18 amino acids.It was recognized that sulphur containig amino acid, tryptophan and valine contents of the algae are short comparing with those of egg and milk.