Medical devices with small dimensions made of superelastic NiTi become more popular, but joining these parts remains challenging. Since laser welding was found to be an option, electron beam welding seems to be an interesting alternative as it provides additional advantages due to the precise beam positioning and the high vacuum. Superelasticity is influenced by microstructure and surface layer composition that are mainly affected by welding process and by heat treatment and therefore will be investigated in the present paper.