Two antifungal antibiotics octacosamicins A and B were isolated from the culture broth of a strain of actinomycetes, which was identified as a strain of Amycolatopsis. These antibiotics were isolated by resin adsorption and purified by column chromatography and preparative HPLC. Both antibiotics were found to be new substances from their physico-chemical properties. They showed broad antifungal spectra.