A study was made on the requirement of individual amino acid and on the relation between the utilization of the amino acids, vitamin B_6 and thiamine in basal medium for the growth of Saccharomyces carlsbergensis. Using 18 amino acids found in casein hydrolysate, the yeast was cultivated under following conditions. (1) Absence of both thiamine and vitamin B_6,(2) presence of thiamine, (3) presence of vitamin B_6 and, (4) presence of both thiamine and vitamin B_6. The amino acids were able to classify into 4 groups by their effects on growth. The requirement of individual amino acid in assay medium for vitamin B_6 was examined by the removal of each amino acid, it was supposed that glutamic acid, histidine, methionine, isoleucine and tryptophan are necessary for the growth of the yeast as nitrogen sources.