The aim of this study was to determine, using a simplex-centroid mixture design, an optimized tempeh formulation with the best physicochemical and antioxidant properties produced from three legumes: common beans, chickpeas and lentils using Rhizopus oligosporus. For this, the proximal composition, WAI, pH, TPC, and antioxidant capacity by DPPH and ABTS radicals were determined for raw legumes. The optimal fermentation conditions were determined by a digital image analysis and the fermentations were performed according to the design. The content of crude and soluble protein, TPC and DPPH of the fermented samples were determined, and a statistical optimization was performed through the maximization of each variable. It was found by optimization that a formulation of 80.81% lentil and 19.19% chickpea presented the best desirability (D=0.75) according to the previously mentioned criteria. This study shows that the combination of legumes exerts a synergistic effect on the physicochemical properties of tempeh.