The present invention relates to a method for the production of a piston (1), composed of a piston upper part (2) and a piston lower part (3), of an internal combustion engine, in which the piston upper part (2) is welded with the piston lower part (3) via a contact surface (4) and thereby a cooling duct (5), delimited therebetween, is formed. It is essential to the invention here that for the production or keeping free of an net opening (6) and/or of an outlet opening (7) of the cooling duct (5) during or immediately after the welding of the piston upper part (2) with the piston lower part (3) at least one pin (8) is held out from the piston lower part (3) in the cooling duct (5) or is pushed therein and is drawn out again after the welding process, so that a welding bead (9) occurring on the welding process does not constrict a cross-section of the net opening (6) and/or of the outlet opening (7). Hereby, the piston (1) can be produced at a comparatively favorable cost.