Different modern techniques are used for optimization of removable partial dentures, laser welding being one of them. The aim of present study is to put in evidence some structural features which may be met at laser joning cobalt based alloys. The experimental alloys are used for long lasting prosthetic pieces. Laser welding equipments was a Mini Laser XXS (Orotig Italia) and the tested samples were welded in butt joint, without filler material. There are presented in comparison results concerning macro and micro structural analysis made on Olympus stereomicroscope and Reichert microscope. Finally a correlation between different welding parameter values and structural features was made. Keywords: removable partial dentures, cobalt s, laser welding, macrostructure, microstructure