The synthesis of state feedback gains that provide robustness against perturbation in deadbeat regulation is considered. The problem is formulated as an unconstrained optimization problem. Through a posteriori perturbation analysis of the closed-loop eigenvalues, the justification of the use of a new objective function to measure the robustness of deadbeat systems is established. The objective function does not require the computation of eigenvectors, and has simple analytical gradient and hessian. A numerical example is employed to illustrate the effectiveness of the proposed method.