The invention relates to a profiled tube for working cylinders without a piston rod having a cylinder chamber which extends in longitudinal direction and a piston guided movably therein and connected to pull means, and a carriage connected to the pull means and guided in a slide guide arranged on the profiled tube. In order to increase the torsional rigidity of a profiled tube for working cylinders having rodless pistons of this type, to guide the piston in a manner secured against turning and, at the same time, obtain a compact structural shape, the present invention provides a profiled tube have a closed single-piece cross section, that the cylinder chamber have an ovoid, preferably elliptical cross section arranged within the cross section of the profiled tube, that pressure-fluid guide channels extending in longitudinal direction are arranged within the cross section of the profiled tube, and that the slide guide is arranged along one of the outer longitudinal sides of the profiled tube and unitarily formed as a single piece with the tube.