Dioscorea esculenta or known as gembili in Indonesian is a tuber that can grow easily in almost tropical areas. Gembili is one of the important food sources in the tropical regions. It contains 22.44% carbohydrate which makes it very potential to be developed into tuber flour. This study aims to improve the quality of gembili flour by assessing the effect of several parameters such as oxidation time, the ratio of slurry, and agent concentration on swelling power level. The optimum condition of the oxidation process was at the ratio of slurry 10% with 2% of H 2 O 2 concentration and 60 min operation time that presented the swelling power level of 7 (g/g). Therefore, this swelling power of gembili flour complies with American wheat standards.