Additive manufacturing (AM) has evolved in recent decades and is nowadays used in a wide range of applications. One of the discussed issues when AM is compared to other manufacturing methods is the excess surface roughness. The method of adding material layer by layer is inherently contributing to a rougher surface, which is not suitable "as manufactured" for many applications. This paper presents the first results on using water jet to decrease the surface roughness of the surfaces of Ti6Al4V ELI and 316L steel manufactured by Electron Beam Melting (EBM®). The surfaces were characterized before and after treatment using profilometry, x-ray diffractometry and scanning electron microscopy. AM can provide new possibilities when it comes to the manufacturing of complex shapes but such components can be difficult to post-process. So a deeper understanding of different post-processing methods for AM materials will open up new possibilities for the wider industrial use of AM.