Accurateyield estimation is of particular importance in microwave component design due to the presence of manufacturing tolerances. Coarse- and fine-mesh space mapping (SM) methodology has been regarded as a powerful tool for facilitating electromagnetic (EM)-based yield estimation, especially when equivalent circuit coarse models are not available. This letter proposes a novel EM-based yield estimation technique using mesh deformation-incorporated coarse- and fine-mesh SM. Through the incorporation of mesh deformation into coarse-mesh simulation, both the coarse-mesh EM responses and the coarse-mesh EM sensitivities change continuously as geometrical parameters change. This allows the proposed technique to use a coarser mesh in building the SM surrogate than the conventional SM technique, thereby accelerating the overall EM-based yield estimation process. The proposed yield estimation technique is demonstrated through two microwave examples.