This study was conducted to evaluate the effect of oxalic acid (OA) pretreatment on carbohydrates released from rice straw particles and wood chips. The results showed that OA treatment accelerated carbohydrates extraction from rice straw particles and wood chips. OA pretreatment dramatically increased the amount of carbohydrates extracted, up to 24 times for wood chips and 2.3 times for rice straw particles. Sugars released from the OA-treated rice straw particles and wood chips increased with increasing treatment temperature and duration. OA treatment also improved the primary physical prope...