AbstractAspergillus ochraceus, grown as a surface culture in a chemically defined medium of sucrose and inorganic salts, gave a high yield of fat (47.5%) the main component acids of which were shown to be myristic (0.2%); palmitic (37.6%); stearic (0.1%); oleic (14.6%); linoleic (45.3%); and linolenic (2.2%). The high content of linoleic acid gives this fat considerable potential importance.