Abstract: A piston-cylinder unit with an adjustable stroke length includes a cylinder having an axis, a closed end and a rod end, a piston rod supported in the rod end of the cylinder in sealed and sliding relation, and a piston received on the piston rod for axial movement relative to the piston and received in the cylinder for axial movement relative to the cylinder. A threaded connections is provided between the piston rod and the piston. A stop surface on the side of the piston facing the rod end of the cylinder and a counterstop surface associated in fixed relation with the cylinder and facing the closed end of the cylinder are engaged when the rod is extended from the cylinder to a full stroke length position. Upon such engagement the piston is held rotationally fixed to the cylinder such that upon rotation of the cylinder about the axis, the piston is rotated relative to the piston rod and is moved axially along the piston rod by the threaded connection such as to change the stroke length.