This paper focuses on analysis of the robustness of full state feedback controlled systems with parametric uncertainties. Both the ability to remain stable and to maintain a prescribed level of performance are assessed. Robustness bounds are developed for a given closed-loop system; these describe the largest magnitude of uncertainty for which the system can both be guaranteed to remain stable and to satisfy a given performance criterion. Furthermore, a maximal robustness bound is developed for a given system that is independent of the choice of controller, but guarantees that for admissible uncertainties, a controller can be found that will satisfy stability and performance criteria. This robustness analysis technique enables the trade-off between performance and robustness to be quantitatively assessed.