This study was conducted to evaluate the effects of chestnut powder on antioxidant activity and quality characteristics ofcookies. 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 contentin chestnut powder and cookies. In addition, the quality characteristics of the chestnut cookies were estimated based on: thebulk density and pH of the dough, spread factor, loss rate, leavening rate, color, texture profile analysis, and sensoryevaluations. The spread ratio, a values, total polyphenol contents, and DPPH free radical scavenging activity of cookiessignificantly increased with increasing chestnut powder (p<0.001), while the leavening rate, L values, b values and hardnessof 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 thatchestnut powder is a good ingredient for increasing the consumer acceptability and functionality of cookies.