Dipodascus uninucleatus Biggs was isolated from a dead pupa of Drosophila melanogaster. Biggs (1937) reported that this fungus grew on Ai variety of media including liquid sugars, potato glucose agar, 1 per cent lactose agar, and malt extract agar. The latter medium permitted the best growth. Dulaney and Grutter (1950) noted that D. uninucleatus failed to grow in a vitamin-free medium, although normal growth resulted in the presence of yeast extract. Their investigation of the vitamin requirements of this yeastlike fungus showed that a mixture of biotin and thiamine gave growth equivalent to that obtained with use of a mixture of 12 vitamins. Addition of nucleic acids did not increase the amount of growth. These investigators also reported that D. uninucleatus utilized ammonium nitrogen, but not urea or nitrate nitrogen. During a study of pigmentation in cultures of D. uninucleatus and Aspergillus niger (Kuehn, 1952; Shanor and Kahn, 1949) it became necessary to investigate the growth responses and requirements of D. uninucleatus. The purpose of this report is to present the results pertaining to the nutritional requirements of this organism.