The objective of this work was to study the kinetics of hemicelluloses extraction and to evaluate factors affecting the rate of xylooligomer and xylose formation during hot-water pretreatment of corn stover. The pretreatments were conducted in a batch reactor at 160-210°C with reaction times of up to 90 min. Yields of xylooligomers, xylose, and sugar degradation products, i.e., furfural, were determined. Under these conditions, sugar yields of up to 92% (as total xylose) were obtained. At the maximum of total xylose recovery, about 85% of the xylose was recovered in the oligomeric form. The release of acetic acid in the hydrolyzate followed a similar kinetic trend to that observed for total xylose release. The time of maximum total xylose recovery corresponded to the same reaction time at which the maximum acetic acid was recovered for all reaction temperatures. This indicates the influence of acetic acid in determining the rate of xylan hydrolysis.