AbstractThe present study aimed to optimize the formulation of buckwheat/lentil gluten‐free beverages fermented withLactobacillus plantarumandBifidobacterium bifidum. Physicochemical parameters of 14 different beverages, such as pH, acidity, total solids, ash, total phenol content, antioxidant activity, and sensory test, were assessed after 24 h of fermentation. The results showed that the numbers of viable cells of lactobacilli and bifidobacteria on the first day of the experiment were 9.9 and 9.6 log (CFU ml−1), respectively, which were over 9 log (CFU ml−1). During 24 h from the fermentation, the number of viable cells for all beverages decreased, which reached an average probiotic count of 8.81 log (CFU ml−1) that was statistically significantly different from the probiotic count before fermentation (p< .05). Cell viability was evaluated and shelf life was estimated during 15‐day refrigerated storage. At the end of the storage (15th day), the beverages contained an average of 8.4 log (CFU ml−1) of live lactobacilli cells and 7.8 log (CFU ml−1) of viable bifidobacterial cells. The optimized levels of independent factors for sprouted buckwheat and lentil flours were 51.96% and 48.04%, respectively. The optimized probiotic beverage was contained 0.25 (% lactic acid) acidity, 5.7 pH, 7.9% total solids, 0.4% ash, 41.02% DPPH, 26.96 (mg GAE/ml) phenol compounds, and 8.65 log (CFU ml−1) probiotic count. The optimized beverage had distinct organoleptic properties on day 15 of refrigerated storage. This study showed thatBifidobacterium bifidumcan be used for the development of potentially probiotic beverage with sprouted buckwheat and lentil.