The effects of different carbon sources (sugars) on the production and molecular properties of exopolysaccharides (EPS) were evaluated in the mycelial liquid culture of a medicinal fungus Cordyceps sinensis Cs-HK1. Galactose or mannosewas used (at 5 g·L

-1

) as a secondary carbon sourcewithglucose (35g·L

-1

) at themass ratioof1:7.Mannose was consumed notably since the first day of culture

but galactose was not even after glucose was exhausted. The volumetric yield of EPS in culture was increased slightly with the addition of galactose and decreased withmannose. The monosaccharide composition of EPS was also different

e.g.

on day 8

the glucose contents of EPS were 76% with the addition of mannose

59% with galactose

comparedwith 62% with glucose only. Themolecular weight distribution of EPS was also affected by the secondary carbon source

being generally lower compared with that with glucose only. The results suggested that the addition of galactose improved the total yield of EPS in culture while mannose can improve the yield of glucan constituent of EPS.