A process for the preparation of letrozole

There is provided a process for the preparation of letrozole, wherein the reaction of an activated bis (4-cyanophenyl) -methane is included with triazole for the preparation of letrozole, and optionally the purification of the Letrozols. Also, highly pure letrozole and a method for cleaning the Letrozols is provided, wherein the precipitation of letrozole, z. B. is incorporated by selective precipitation from a reaction mixture and / or by subjecting the Letrozols one or more crystallizations.