For increasing cellulose accessibility to the enzymatic attack, the pretreatment is a necessary step to alter some structural characteristics of cellulosic materials. As a new pretreatment method, microwave irradiation on cellulose dissolution pretreatment with ionic liquids (ILs) was investigated in this study. Microwave irradiation not only enhanced the solubility of cellulose in ILs but also significantly decreased the degree of polymerization of regenerated cellulose after IL dissolution pretreatment, resulting in significant improvement of cellulose hydrolysis. The rate of enzymatic hydrolysis of cotton cellulose was increased by at least 12-fold after IL dissolution pretreatment at 110 degrees C and by 50-fold after IL dissolution pretreatment with microwave irradiation. Our results demonstrate that cellulose pretreatment with Its and microwave irradiation is a potential alternative method for the pretreatment of cellulosic materials. (C) 2010 Elsevier Ltd. All rights reserved.