The purpose of this study was to investigate the quality characteristics and antioxidative effect of cookies prepared with Curcuma longa L. powder (0, 1, 2, 3, 4%) substituted for flour. The pH of cookie dough decreased significantly in response to the addition of all levels of Curcuma longa L. powder (CLP). However, there were no significant differences in dough values among the test groups. Furthermore, when the spread factor values were compared among the groups, they were found to be inversely proportional to the CLP concentration. In addition, Hunter’s color L value significantly decreased with increasing CLP content, whereas the a and b values increased. According to textural measurements, substitution of 1~4% for CLP resulted in increased hardness, cohesiveness, springiness, and brittleness when the samples were compared to the control. The results of sensory evaluation showed that the cookies containing 2% CLP had the highest scores. The acid value, peroxide value, and thiobarbituric acid value were all lower in cookies with 2% and 3% CLP than in cookies made with 4% CLP and control cookies.