Abstract: A hydraulic radial piston motor with a cam disc and a cylinder block with a number of pistons running in cylinders in the block presses rollers against the cam disc in such a way that a torsional moment arises. The rollers are formed with guide members running in slots in guide units which take up tangential forces. The rollers are mounted in roller cages which are formed with hydrostatic bearings. At their outer end each piston is formed with a part-spherical bearing surface and the roller cage has a cooperating part-spherical bearing surface, which allows angular movements between the roller cages and the pistons in all directions.