Abstract: To find a suitable culture medium for both cell growth and taxol production, cell suspension cultures of Taxus cuspidata var. nana were conducted using of six kinds of culture medium (B5C2, S2FG, SH, S8, F4 and F4G4). Taxol was produced in all media. However, the amount of production of taxol was largest when the cell cultures were conducted in the F4G4 medium. Furthermore, chito-oligosaccharides prepared by a partial hydrolysis of chitosan and each constituent of the chito-oligosaccharides (from glucosamine to chito-heptaose) as elicitors, gibberellin A3 (GA3) as a plant growth regulator and phenylalanine as a biogenetic precursor were added to the cell suspension cultures to enhance taxol production. It was found that the amount of production of taxol was increased 7.0 fold over the control by addition of chito-heptaose. However, little if any effect of GA3 and phenylalanine on taxol production was recognized.