The purpose of this study was to evaluate cookies prepared with five different quantities (0, 5, 10, 15, and 20%) of watermelon powder (WP). This study analyzed quality characteristics, consumer liking, and CATA (check-all-that-apply) of the samples. The density and pH of the cookie dough and the L-value of the cookies tended to decrease as the amount of watermelon powder increased (p<0.05), whereas the spread factor, a-value, and hardness of the cookies tended to increase as the amount of watermelon powder increased (p<0.001). The b-value tended to increase up to WP10, but it tended to decrease from WP15 (p<0.001). The results of the evaluation of consumer liking showed that overall liking was the highest for WP5 and lowest for WP20 (p<0.05). In the analysis of the CATA survey, the main reasons for liking for all the samples were ‘Appearance’, ‘Color’, ‘Sweet taste’, ‘Nutty odor/flavor’, ‘Crispiness’, and ‘Familiarity’. WP5 showed the most diverse reasons for being liked. The common reason for disliking samples with the addition of watermelon powder was ‘Residual feel in the mouth’. In the correspondence analysis, attributes of ‘Stale taste’, ‘Clean taste’, ‘Softness’, ‘Familiarity’, ‘Moistness’, ‘Color’, ‘Blandness’ were detected in the WP0 and WP5. The results indicate that WP5 with a 5% supplementation of watermelon powder is appropriate for improving the quality and consumer acceptability of the cookies.