Kenaf (Hibiscus cannabinus) has received considerable attention as a renewable resource because of its fast growth and low lignin content. In the present study, a combination pretreatment of kenaf core using electron beam irradiation (EBI) and dilute alkali was investigated to improve the sugar yield in enzymatic hydrolysis. In the first step, EBI of the kenaf core was performed at various doses ranging from 100 to 500 kGy. The electron beam-irradiated kenaf core was then autoclaved with 3% dilute alkali at 120 degrees C for 5 h. The pretreated kenaf core was finally subjected to enzymatic hydrolysis at 50 degrees C for 24, 48, and 72 h by Celluclast 1.5 L (70 FPU/mL) and Novozyme-188 (40 CbU/mL). A total sugar yield of 72.4% was obtained with a 63.9% yield of glucose from pretreated kenaf core after 72 h of enzymatic hydrolysis. To further analyze effectiveness of EBI pretreatment, characterizations of kenaf core by a two-step process of EBI-alkaline pretreatment were also investigated.