. Y and P + Y were more effective for the cordycepin production. In both cases, the average rate of glucose consumption between 0 and 9 days of culture showed a moderate level com-pared to the other cases. It suggests the existence of the optimal rate of glucose consumption during the cordycepin production, which could be related to the rate of the cell growth. In other words, the cordycepin biosynthesis is controlled by the balance between the conditions of the residual nutrients and the rate of cell growth. Cordycepin production is also not proportional to the average rate of cell growth in a previous report [36]. Subse-quently, the media containing peptone (P) and yeast extracts (Y) as nitrogen sources were investigated in detail. The total con-centration of the nitrogen sources was fixed at 10 g/l and the P/Y ratio was changed from 1/0 to 0/1