[en] This paper reported the optimization of glucose production from ammonia pre-treated oil palm trunk biomass via enzymatic saccharification process using response surface methodology (RSM). A set of experiment was computed by face centered central composite design (FCCCD) using Design Expert software to statistically evaluate the findings. Three independent variables namely: temperature (35 - 55 degree Celsius), pH (4.5 - 6.5) and enzyme ratio (cellulase: β-glucosidase; 3:1 - 7:1) were investigated under the given conditions designed by RSM. The experimental result (4.964 ± 0.006 g.L"-"1) was in good agreement with RSM model prediction (4.958 g.L"-"1) with an error less than 0.2 %. The RSM design has been proven to successfully predict the glucose response in this study. (author)