Obtaining ethanol from sugar cane bagasse is regarded as a possible source of this alternative fuel for two reasons: it does not hinder food accessibility and, reduces solid waste generation from sugar cane processing. Cellulose, hemicellulose and lignin are the main components of bagasse: cellulose can be hydrolyzed into glucose yet hemicellulose is hydrolyzed into glucose and other pentoses, where xylose is abundant. Unlike glucose, xylose can only be fermented by a limited number of yeast strains. During this project, the main objective is to determine the kinetics and ethanol yields of xylose-fermenting yeast strains Pichia stipitis NRRL Y-11545, Pachysolen tannophilus NRRL Y-12885, Candida shehatae NRRL Y-12858, and Candida shehatae NRRL Y-1702 to screen for the most efficient xylose fermenting strain. Batch fermentations for each strain were conducted at constant pH, temperature and agitation speed of 4.5, 32°C and 65 rpm, respectively. Batch culture data and ethanol production were determined by means of periodical optical density measurements, dry biomass weighing and HPLC analysis for glucose, xylose and ethanol. The maximum specific growth rate, μ_max, and overall ethanol yield, Y_P/S, were obtained in order to develop a mathematical model to describe the xylose fermentation kinetics. Based on previous studies, Pichia stipitis offers the highest ethanol yield from xylose fermentation. Ultimately, the most efficient xylose fermenting strain will be employed along with Saccharomyces cerevisiae in a subsequent study on co-fermentation of glucose and xylose to implement an efficient cellulosic ethanol process design.