Abstract: A hydropneumatic spring, which is preferably articulately arranged between a vehicle body and a wheel guiding part in motor vehicles, has a fluid-filled cylinder which is entered by an outwardly sealed piston rod having a piston connected at the internal end. For altering spring force-deflection progressivity characteristic, a first working chamber of the cylinder is in constant hydraulic connection with a first spring energy store device and a second working chamber of the cylinder is in constant hydraulic connection with a second spring energy store device via a second valve device via a first valve device. In a mid spring deflection range, a second spring energy store device is connected via a second valve device and a bypass to the first spring energy store device. The bypass includes an axially extending channel arranged between the first working chamber and the second working chamber.