A bilayer tablet, which consisted of telmisartan and amlodipine besylate, was formulated based on a Quality by Design (QbD) approach. The control and response factors were determined based on primary knowledge and the target values of the control tablet (Twynsta®). A D-optimal mixture design was used to obtain the optimal formulations in terms of D-mannitol, crospovidone, and MCC for the telmisartan layer, and CCM-Na, PVP K25, and Prosolv for the amlodipine layer. The quantitative effects of the different formulation factors on the response factors were accurately predicted using the equations of best fit and a strong linearity was observed between the predicted and actual values of the response factors. The optimized bilayer tablet was obtained using a numeric optimization technique and was characterized compared with a control (Twynsta®) by using various physical evaluations and in vivo pharmacokinetic parameters. The physical stability of Telmiduo® was greater than that of Twynsta® owing to the improvement of formulation factors. The in vivo pharmacokinetic parameters suggested that Telmiduo® might have pharmaceutical equivalence and bioequivalence with Twynsta®. Therefore, the bilayer tablet that consisted of telmisartan and amlodipine besylate could be produced using a more economical and simpler method than that used to produce Twynsta®. Moreover, the suitability of QbD for effective product development in the pharmaceutical industry was shown.