This work describes the effect of insecticide bifenthrin on Lactobacillus plantarum and Saccharomyces cerevisiae. Growths of used microorganisms in growth media supplemented with pesticide were studied. Determination of bacterial and yeast fermentation efficiency in wheat supplemented with bifenthrin was conducted. Additionally, investigation of bifenthrin dissipation during microbiological activity was performed. Experiments applying bifenthrin in different concentrations highlighted a negligible impact of the pesticide on the growth of L. plantarum and S. cerevisiae. This insecticide overall negatively affected the yeast fermentation of wheat, while its presence in wheat had a slight negative impact on lactic acid fermentation. The results of bifenthrin dissipation during lactic acid and yeast fermentations of wheat showed that activities of L. plantarum and S. cerevisiae caused lower pesticide reductions. Average bifenthrin residue reduction within samples fermented with L. plantarum was 5.4 % (maximum ~16 %), while within samples fermented with S. cerevisiae, it was 11.6 % (maximum ~17 %).