Biomass of food yeast Kluyveromyces fragilis (MTCC 188) grown on deproteinized whey supplemented with 0.8% diammonium hydrogen phosphate and 10 ppm indole-3-acetic acid, had a crude protein content of 37%. The true protein content based on nitrogen fractionation procedure was 28.1%. Total nucleic acid content was 4.82%. This amount does not appear to be toxicologically offensive. Crude fiber, ash, and lipid content of K. fragilis dry cells were found to be 4.9%, 16%, and 7.8%, respectively. Essential fatty acids of both omega-3 and omega-6 series were found present in the fat of the yeast and represented 21.5% of the total fatty acids. All the essential amino acids were present in the proteins of K. fragilis; however, sulfur containing amino acids were found in lower amounts. Calculated protein scores indicate moderate biological value. B vitamins in the biomass were present as expected, but folic acid and pyridoxine were present in high concentration.