Abstract: A hydraulic piston machine is disclosed, having a cylinder body, which has at least one cylinder, in which a piston is arranged to move back and forth and bears by way of a slide shoe against a control surface, and having a pressure plate which holds the slide shoe in engagement with the control surface. It is desirable to be able to operate such a machine also with a fluid that has no or only poor lubricating properties. To that end, the pressure plate and/or the control surface is provided with a layer of a friction-reducing plastics material at least in one of the regions with which in operation they rub against other parts.