On the basis of the synchronicity of geochronological data and the similarity of granite types, it is proposed that the mid-Carboniferous Fichtelgebirge/Erzgebirge Batholith in the Saxothuringian Zone of the central European Variscan Fold Belt and the South Bohemian Batholith in the Moldanubian Zone (including the intervening Oberpfalz and Bavarian Forest granite areas) belong to one coherent and cogenetic, ca. 400 km long plutonic megastructure. Unlike older (syn-collisional) plutonic structures in the Bohemian Massif, this Saxo-Danubian Granite Belt (nov. nom.) has developed discordant to the Devonian/Early Carboniferous collision-related tectonic architecture of the Bohemian Massif. It is argued that the Saxo-Danubian Granite Belt formed in response to a post-collisional detachment of lithospheric mantle below the south-western sector of the Bohemian Massif.