The concept of metamaterials and metasurfaces have attracted much attention owning to their extraordinary properties recent years. Various applications have been developed for such sub-wavelength artificial electromagnetic structures. The RCS reduction technology is one of the most promising area for applications. For example, metamaterial absorber, rasorber, diffusive scattering metasurface, and RCS reduction designs based on both absorption and scattering. This special session aims to call for recent achievements including all the RCS reduction techniques and applications based on metamaterials/metasurfaces.