When Fusarium oxysporum f. niveum Snyder et Hansen was shake-cultured for 3∼4 days at 28°C on 5% glucose-potato extract, a pigment was enormouly formed in the mycelium. The pigment changes color from red to blue when the reaction of the medium changed from acid to alkali. The pigment was isolated from the HCl (3:1)-treated mycelium by extraction with chloroform. The purified pigment was red, platelet or lens-shaped, m. p. 310∼1°C. (decomp.), empirical formula being C20H16O8. It was proposed from the results of acetylation, methylation, infrared absorption spectra, and other examinations, that it is probably a quinoid pigment having two hydroxy and two methoxy radicals, and it may be identified with lycopersin, a pigment of F. lycopersici, isolated and named by Kreitman et al. It seems that this pigment is universally present in Fusaria belonging to the species oxysporum.