Cookies are snack commonly made from wheat floer. In an effort to reduce dependency problem needs what flour at this point, ganyong (canna edulis Ker) starch which is a carbohydrate source can be used as an alternative to wheat flour in making cookies. This study aimed to determine effect of use of ganyong starch as a substitute of wheat flour on quality of resulting cookies. This research used completely randomized design (CRD) by a factor of 5 treatments and 3 replications. The treatments studied were proportions ganyong starch:wheat flour (A=0%:100%,B=25%:75%,C=50%:50%,D=25%:75%,e=100%:0%.The results show that treatment of ganyong starch proportion 75 % and 25 % wheat flour is the best treatment results in cookies that meet SNI 01-2973-1992 with water content of 3.05% w/w. protein of 6.43% w/w, ash content of 0.97% w/w and total plate count of 2.4x10 kuadrat colonies/g.preference ranking value:color of 4.30 (like), taste of 3.90 (like), aroma of 4.90 (like) and texture of 3.90 (like).