This study was conducted to evaluate the effects of chestnut powder on antioxidant activity and quality characteristics of cookies. Cookies were prepared using different amounts of chestnut powder (0, 5, 10, 15 and 20% to the flour quantity). The antioxidant activity was estimated by measuring DPPH free radical scavenging activity and the total phenolic content in chestnut powder and cookies. In addition, the quality characteristics of the chestnut cookies were estimated based on: the bulk density and pH of the dough, spread factor, loss rate, leavening rate, color, texture profile analysis, and sensory evaluations. The spread ratio, a values, total polyphenol contents, and DPPH free radical scavenging activity of cookies significantly increased with increasing chestnut powder (p<0.001), while the leavening rate, L values, b values and hardness of the cookies significantly decreased with increasing chestnut powder (p<0.05). The sensory evaluation scores for the 15% chestnut powder cookie groups ranked significantly higher (p<0.05) than the other groups in overall preference, appearance, taste, color, chestnut taste, oily flavor, and aftertaste. Taken together, the results of this study suggest that chestnut powder is a good ingredient for increasing the consumer acceptability and functionality of cookies.