The invention relates to a method for producing a tubular structural part by means of hydroforming. An assigned end of a supporting tube (1) is inserted into an opening in an end piece (2) and then widened by a pressurized fluid being applied to it and is connected to the end piece (2) with a press fit. The opening (9) has a first portion (10a) with a first inner cross section, which is greater than the outer cross section of the assigned end of the supporting tube (1). According to the invention, the first portion (10a) is adjoined by a second portion (10b), in a step-shaped manner so as to form an edge (11). The inner cross section of the second portion (10b) is smaller than the outer cross section of the assigned end of the supporting tube (1). In the method according to the invention, the supporting tube (1) is first inserted with its corresponding end into the first portion (10a), before the edge (11) cuts into the material of the supporting tube (1) in a further pushing-in movement.