The effects of medium composition and fermentation parameters on simultaneous production of mycelia and intracellular polysaccharide by medicinal mushroom, Cordyceps jangxiensis were investigated in shake-flask Cultures using desirability functions. The optimal conditions were obtained via the associated desirability as follows: 40 g/l of molasses glycerol. 5 g/l of peanut steep meal. 6 g/l of yeast extract. 1 g/l of KH2PO4, 0.5 g/l of ZnCl2, 0.5 g/l of MgSO4, initial pH at 6, cultivation temperature at 28 degrees C, 200 nil of medium working volume in a 500 ml flask and 5% (v/ v) of inoculum size. Under these conditions, the production titer of mycelia and intracellular polysaccharide reached 24.5 and 8.9 g/l. respectively, after a 9-day submerged cultivation. The use of desirability functions was proved effective in optimizing multi-response fermentation processes and it is readily applicable to other fermentation systems. (c) 2006 Elsevier Ltd. All rights reserved.