Present report will elucidate the occurrence of polyphosphoinositides, such as di- and triphosphoinositides, in a strain of baker's yeast as well as in beef brains. In order to remove other phospholipids from polyphosphoinositides, phosphoinositide fraction was reextracted with acidified chloroform-methanol (C-M) mixture after having extracted twice with neutral (C-M) mixture from yeast. The phosphoinositide fraction was further purified by the methods of Folch₁₃₎, Folch₁₄₎, and Hendrickson etal. ₁₂₎ in this order. The purified inositides were chromatographed on DEAEcellulose column comparing with “Folch's Diphosphoinositide” fraction prepared from beef brain. Three peaks were obtained on the column chromatogram. The euates corresponding to each peak were combined, dialyzed against water, and then lyophilyzed. Each fraction was identified on formaline-treated paper and silica gel thin layer chromatograms as monophosphoinositide plus a trace of phosphatidyl serine, di-, and triphosphoinositides, respectively. The diphosphoinositide was further characterified from the rate of inositol to phosphorus.