SUMMARYThe utilization of various carbon and nitrogen compounds byRhizopus oligosporusSaito NRRL 2710 was investigated. The principal components of the soluble carbohydrates of soybeans, i.e., stachyose, raffinose, and sucrose, were not utilized as sole sources of carbon. Common sugars such as glucose, fructose, galactose, and maltose supported excellent growth as did xylose. Various vegetable oils could be substituted for sugars as sources of carbon with excellent growth.Ammonium salts and such amino acids as proline, glycine, aspartic acid, and leucine were excellent sources of nitrogen. Other amino acids were less suitable, and tryptophan supported no growth at all. Sodium nitrate was not utilized as the sole source of nitrogen.Experiments with citrate-buffered media demonstrated thatR. oligosporusgrows well at a pH as low as 2.6–3.0.