Abstract:The composition and content of fatty acids in three marine(Chaetoceros simplex,Pavlova virides,Platymonas sp.)and three freshwater microalgae(Chlorella pyrenoidosa,Scenedesmus obliquus,Spirulina maxima)were measured. Major saturated fatty acids in the marine microalgae were characterized by those with 14-20 carbons, while those in the freshwater microalgae were only C16:0 and C18:0.The monounsaturated fatty acids in both marine and freshwater microalgae were mainly C16:1ω7 and C18:1ω9. Major polyunsaturated fatty acids in the marine microalgae were Eicosapentaenoic acid an d Docosahexaenoic acid, while those in the freshwater microalgae were polyunsaturated fatty acids of 18 carbons.