Lignocellulosic agricultural wastes seem to have greater potential alternative resource for the production of bioethanol because of its many benefits. However, effective pretreatment which combines physical, chemical, biological, and thermal methods is a crucial prerequisite for a cost-effective lignocellulosic bioethanol production process. The recovery of cellulose and the porosity of the substrate for saccharification are enhanced by the removal of hemicellulose and lignin. In this work, a microwave-assisted DES pretreatment for the fractionation of corncobs was used. Pretreatment was carried out using varying microwave power (300, 550, and 800 W), irradiation times (10, 20, and 30 min), and DES types (lactic acid/choline chloride, glycerol/choline chloride, and ethylene glycol/choline chloride). Proximate analysis showed that the corncob feedstock contained 3.45 wt/wt% of moisture, 1.5 wt/wt% of ash, 76.53.45 wt/wt% volatile matter, and 18.55 wt/wt% content of fixed carbon. The percentages of cellulose, hemicelluloses, and lignin of corncob feedstock are 49.4%, 31.7%, and 17.4%, respectively. The results indicated that the maximum (85.15%) amount of lignin Removal was achieved at 20 min, 800 W with Ethylene glycol: Choline chloride DES. On the other hand, the maximum yield of fermentable sugar (37.9 mg/mL) was achieved at 20 min, 550 W with ethylene glycol/choline chloride.