The primary objective of this study was to determine the optimal mixing ratio in preparing Omi-Galsu concentrate. By varying the amounts of Omija extract, mung bean juice, and sugar in the concentrate mixture, we found that pH increased with greater amounts of Omija extract and sugar. According to sensory evaluations, sugar and total free sugar contents were highest when the mixing ratio was 1:1:20%(Omija extract, mung bean juice, and sugar respectively). This ratio also presented the most attractive color and highest overall acceptability.