Three agricultural wastes with high xylan content (barley bran, corn cobs and corn leaves) were hydrolysed with dilute sulphuric acid solutions under a variety of operational conditions in order to obtain xylose solutions suitable as fermentation media. The operational conditions for hydrolysis were selected on the basis of both the kinetic models developed for xylose generation and the concentrations of reaction byproducts affecting fermentation. Hydrolysates were supplemented with nutrients and fermented withDebaryomyces hanseniiwithout any previous detoxification stage. Experimenal data concernmg batch fermentations are compared to the results obtained in the fermentation of hydrolysates fromEucalyptuswood, a typical raw material for prehydrolysis processes.