The application of the differential evolution method in two important areas of applied electromagnetics is discussed in this chapter. The first one refers to the synthesis and design of array antennas, for which differential evolution, as well as other evolutionary algorithms, is now considered a fundamental design tool. The second one concerns the diagnostic applications faced as a result of using radiofrequency and microwave imaging techniques. Being based on the inverse scattering problem, these techniques suffer from nonlinearity and ill posedness. The differential evolution method has been successfully proposed for optimizing this multimodal and complex inverse problem. The chapter includes a brief review of some results recently published in the scientific literature concerning the application of differential evolution to the above-mentioned problems. Moreover, the main contributions of the authors in these areas are reviewed and discussed. Finally, some new results are reported.