In this study, the physicochemical properties of buckwheat flour and quality characteristics of brown-rice doughs containing various concentrations of buckwheat flour stored at $-18^{circ}C$ for 4 weeks and fermented were studied. The total polyphenolic contents, electron donating ability (EDA) of 0.5%, gelatinization onset temperature (To), gelatinization peak temperature (Tp), and gelatinization conclusion temperature (Tc) of buckwheat flour were 1,920.10mg%, 6.95%, $70.11^{circ}C$, $78.21^{circ}C$, and $84.05^{circ}C$, respectively. There were no significant differences in the amount of yeast between brown-rice Jeung-pyun dough samples containing different levels of buckwheat flour and stored for different time periods. The amounts of carbon dioxide gas evolved from the brown-rice doughs were increased by increasing the concentration of buckwheat flour. The pH of brown-rice dough samples decreased with increasing storage period. Therefore, frozen brown-rice dough containing 6-15% buckwheat flour and stored for 3 weeks were the most desirable.