In a method of treating a nitrided/nitrocarburized workpiece, at least a portion of the workpiece is subjected to a first step in which at least one laser beam is moved in at least one pass over the portion, until the surface layer of the portion is transformed in part or in full, and until the distribution of the nitrogen concentration in the diffusion zone is modified. In a second step at least one laser beam is moved in at least one pass over said portion so as to enable the nitrogen concentration in the underlying diffusion layer to be reduced.