A water soluble antifungal antibiotic, Solumycin, was separated from the culture broth of Streptomyces sp. LAM-593, isolated from soil, by butanol extraction, alumina-, 1st and 2nd Sephadex LH-20 column chromatography. The substance was pale yellow crystal which gave a single spot at Rf value 0.24 with ethanol-ammonia water-water (8 : 1 : 1), 0.46 with butanol-ethanol-water (5 : 1 : 4), 0.84 with 50% methanol on silica gel TLC. It was dissolved well in water, methanol and acidic aq. butanol but not in ethanol, acetone, ethyl acetate, chloroform, acetic acid etc. , and gave positive Fehling and Molish reaction. The UV spectrum in methanol showed absorption at 342, 361, 380, and 404 nm. The antibiotic was active against fungi such as Candida, Cryptococcus, Saccharomyces, Trichophyton and Trichosporon, but not to bacteria such as Bacillus, Escheyichia and Staphylococcus.