Abstract: The invention relates to a method and an apparatus for straightening a workpiece, especially a crankshaft, with a theoretical axis and at least one fillet running circularly about this axis, by exerting a pressure on at least one preselected section of the wall defining the fillet, with a tool that can be moved transversely of the axis and laid into the fillet. To reduce the great straightening forces to be applied in the use of known methods and apparatus, the straightening is performed according to the invention by cold-rolling the fillet walls and with the aid of a modified hard-rolling device, the control systems are provided with measuring means for determining the deviations from true running of the main journals of the crankshaft and actuators for the adjustment of the forces applied by the pressure rollers to the fillet walls according to the particular rotary angular position of the crankshaft to values intended for the straightening of the main journals.