Rice straw was treated using hot compressed water with or without phosphoric acid for enzymatic saccharification. The yields of xylose and glucose obtained from the treatment of the rice straw using hot compressed water without phosphoric acid were low. However, when 0.7% phosphoric acid solution was added to hot compressed water, the yield of xylose increased remarkably, and the highest yield (71%) was obtained at 160°C. Furthermore, the yield of glucose from the treated rice straw by enzymatic saccharification using an enzyme cocktail with a cellulase loading of 2 FPU/g- rice straw was 86%. It clarified that the hot compressed water treatment with phosphoric acid was effective in lowering the enzyme loading compared with the original hot compressed water treatment.