This experiments was designed to evaluated the chemical components and nutrition of Aspergillus fumigatus cells. This dried fungal mycellia was consist of crude protein 48.5%, crude lipid 2.9%, carbohydrate 44.7% and total ash 3.4%, respectively. The major fatty acid of total lipid were 27.9% of linoleic acid, 24.6% of oleic acid, 15.4% of palmitic acid and 10.6% of linolenic aicd. Amino acid analysis indicated that the protein was rich in aspartic acid, glutamic acid, leucine, lysine but poor in cystein, methionine, histidine. The fungal cake of Aspergillus fumigatus, when dried and specially processed, has been found to serve as a source of protein in place of soybean meal in the diet of experimental mice. Animal were fed a control diet first, and an incease in weight proved the formulation to be satisfactory. At the end of a 30-day period, the experimental mice showed increases in weight comparable to those of the control animals. The net protein efficiency ratio for the control diet was 3.42$pm$0.15 and the fungal protein and succinylated fungal protein with DL-methionine they were 3.12$pm$0.39 and 2.98$pm$0.06 respectively. This supports the view that dried and succinylated fungal protein can be substituted as a protein source.