Eight strains of Pseudozyma fusiformata were examined for antifungal activity. All of them had the same spectrum of action and were active against many species of yeasts, yeast-like and filamentous fungi. They secreted glycolipids, which were purified from the culture liquid by column and thin-layer chromatography. According to nuclear magnetic resonance and mass-spectroscopy experiments all strains produced ustilagic acid, a cellobioside-containing 2,15,16-trihydroxypalmitic acid as aglycon, 3-hydroxycaproic acid and acetic acid as O-acylic substituents.