Sugarcane bagasse, an agricultural residue plentiful in Brazil, was utilized for xyli tol production by a bio technological process. A medium fermentation prepared with this xylose-rich biomass at an oxygen transfer volumetric coefficient of 10/h(1) and different initial pH values was inoculated with cells of Candida guillieirmondii FTI 20037. The maximum values of xylitol and cell volumetric productivities (Q(p) = 0.56 g/[L.h] and Q(x) = 0.11 g/[g.h]), xylitol yield factor (Y-p/s = 0.79 g/g), and xylose uptake rate (qs = 0.197 g/[g.h]) were attained at pH 7.0 without further pH control. The results show that the yeast performance was influenced by the pH, an important bioengineering parameter in this fermentation process.