Xylitol production parameter optimization using a newly isolated Candida sp. was performed using Test plan L18, available in the form of an orthogonal array and a software for automatic design and analysis of the experiments, both based on Taguchi approach. Optimal levels of physical parameters and key media components namely temperature, pH, agitation, inoculum size, corn steep liquor (CSL), xylose, yeast extract and KH2PO4 were determined. Among the physical parameters, temperature and agitation contribute higher influence. Media components CSL, xylose concentration and KH2PO4 play an important role in the conversion of xylose to xylitol. The yield of xylitol under these optimal conditions was 78.9%. (C) 2003 Elsevier Ltd. All rights reserved.