In this study, two-stage process using liquid hot water pretreatment (LHW) was proposed to recover C5 and C6 sugars from cassava straw. In the 1st stage, biomass was treated at varying temperatures (160-200 degrees C) and reaction time (15-105 min). In the 2nd stage, the remaining solid after 1st stage was treated under various reaction conditions (190-210 degrees C, 30-90 min). After two-stage LHW pretreatment, the pretreated solid contained a large amount of cellulose and subsequently was highly digested by cellulase. The optimal pretreatment conditions were 180 degrees C and for 60 min (LogR(o) of 4.13) for 1st stage pretreatment, and 200 degrees C and for 20 min (LogR(o) of 4.25) for 2nd stage pretreatment. The yield of C5 sugars of 83.15% by two-stage LHW pretreatment. Meanwhile, using 31 mg/g glucan- CTec2 enzyme to treat remaining solid after the two-stage treatment, the yield of C6 sugars achieved 85.02%.