This study examined the effects of whole amaranth substitutions at various proportions and evaluated the cookies baking behavior. Six types of formulations of cookies were prepared with whole amaranth flour ranging from 20, 40, 60, 80, and 100%. These cookies were evaluated for physical (thickness, diameter, spread ratio, and bake loss), textural, and organoleptic attributes. The diameter and spread ratios were found to be higher in whole amaranth flour cookies 52.20 mm and 6.46, respectively, as compared to other blends (20–80%) of cookies from 51.37 to 51.92 mm and 6.13 to 6.36, respectively. Textural measurement showed that hardness of cookies decreased with the addition of amaranth flour. Whole amaranth flour cookies required least snap force (72.4 N) compared to control (whole-wheat flour) cookies (145 N). Sensory data indicated that the amaranth cookies with up to 60% were acceptable, while additional amaranth flour resulted in a decreased mean score for overall acceptability.