Abstract: The invention relates to an apparatus for the assembly and disassembly of hydraulic cylinders, composed of a pedestal-like machine frame having horizontally arranged guide means which bear, in displaceable manner, a receptacle for the cylinder barrel of the hydraulic cylinder, at least one receptacle for a support and a receptacle for a tool, and furthermore having a holder for fixing the piston rod of the hydraulic cylinder. According to the invention, the holder for fixing the piston rod has a centering carriage which is driven by a centering spindle and which comprises a piston rod receptacle, wherein the holder is designed to be rotatable about the longitudinal axis of the machine frame and the rotational movement is realized by means of a torque-controlled electromotive drive.