To cope with the threats of a harsh environment containing energetic particles, scientists and engineers have been developing mitigation strategies and hardening techniques to improve the resilience of electronic systems. Considering that the radiation environment and the operation conditions are known, as it will be shown in this chapter, several techniques can be applied to increase the robustness of a circuit. The radiation hardening techniques can be adopted during the manufacturing process of a technology or, in a higher level, in the circuit design phase of the component. While process-based techniques offer undeniable efficiency, hardening techniques at the design level are the main focus of this chapter thanks to their several advantages.