The objective of this paper is to investigate the impact of two commonly used turbulence models in Reynolds Averaged Navier-Stokes simulations on three-dimensional optimum design obtained with the gradient-based deterministic aerodynamic shape optimization in transonic, viscous, turbulent flow. The main contribution of this study to aerodynamic design area is to evaluate the impact of turbulence models on the computational cost, optimal shape and its performance obtained with deterministic optimization. The two turbulence models investigated include Spalart-Allmaras and the Menter’s Shear Stress Transport models. In this study, Free-Form Deformation is utilized as shape parameterization technique. The results of the current study show that deterministic design tends to reduce the impact of the turbulence model selection on the optimum shape and performance at deterministic Mach number. It is also observed that the computational cost of optimization is almost constant for each turbulence model.