Microwave-assisted ammonium hydroxide (NH(4)OH) followed by phosphoric acid (H(3)PO(4)) treatments were used to release monomeric sugars from Miscanthus sinensis grown in Cha-Chueng-Sao province, Thailand. Treatment with 1.0% (w/v) NH(4)OH, 15:1 liquid-to-solid ratio (LSR) at 120 degrees C temperature for 15 min liberated 2.9 g of monomeric sugars per 100 g of dried biomass, whereas the corresponding yield for a treatment with 1.78% v/v H(3)PO(4), 15:1 LSR at 140 degrees C for 30 min was 62.3 g/100 g. The two-stage pretreatment, treatment with NH(4)OH at 120 degrees C temperature for 15 min followed by treatment with H(3)PO(4) at 140 degrees C for 30 min, impressively provided the highest total monomeric sugar yield of 71.6 g/100 g dried biomass. (C) 2011 Elsevier Ltd. All rights reserved.