In this study, a BOX-BEHNKEN design (BBD) of response surface methodology was used to investigate the effects of the amount of bran, the amount of yeast and the fermentation time on the amount of phytic acid in bread. The goal of first order factorial experiment is to identify the optimum levels of independent variables for the dependent variable. In this study, the implementation of first order response surface model and interpretation of the results were based on a 3(k) Box- Benhnken (BBD) experimental design with one replicate. RESULTS: The calculation of the data for the first-order response surface model revealed that R-2 was 99,5% and that the model described most of the variance in the dependent variable (phytic acid). CONCLUSION: According to the results of the Box-Behnken experimental design (BBD), it was found that the amount of bran and the fermentation time had highest effect on phytic acid and that the amount of yeast, either alone or in any interaction, had no effect on the amount of phytic acid. Thus, it was concluded that optimal use of the amount of bran and fermentation time in the production of high-quality bread could prevent several diseases in future.