Additive manufacturing or 3D printing is becoming more and more common in industry fabrication, especially for spare parts which cannot be found easily on the local market and for tailor made parts. For large parts and due to its size limitations, it is sometimes required to join 3D printed parts with other 3D printed parts or conventionally produced parts. In this work, 3D printed flat plates 4mm thick were prepared by direct laser sintering of SS316L powders. Mechanical properties and microstructure were investigated. Elongation and maximum tensile stress of 3D printed flat plates are with 1.3% and 704MPa smaller than the values 2% and 1241MPa of cold-rolled SS316 parts. The 3D printed flat plates were joined by welding using TIG welding, plasma welding and laser welding. The welded joints were tested for their mechanical properties and microstructure. For the used welding conditions, the fracture occurred outside the weld zone. The maximum stress of the welded parts is 65-80% of 3D printed flat plates. The elongation of the welded parts is above 3%.